Dipartimento di Chimica and IMC-CNR, Università “La Sapienza”, Box 34  Roma 62, P.le Aldo
Moro 5, 00185 Roma, Italy; CEA/Saclay, SCM (CNRS URA 331), Bât. 125, 91191 Gif-sur-Yvette,
France.
S2
S3 – S5
S6
S7
S8
S9
S10
1
1
General methods
Synthesis of compounds 2  7
1 H and 13 C NMR spectra of compound 2 .
H and
H and
13
13
C NMR spectra of compound
C NMR spectra of compound
3
4
.
.
1 H and 13 C NMR spectra of compound 5 .
1 H and 13 C NMR spectra of compound 6 .
S11 1 H and 13 C NMR spectra of compound 7 .
S12 Figure S1 with representative HPLC analyses
S13 – S16 Figures S2 – S5 with representative 1 H NMR analyses
S17 – S19 Crystal data and displacement ellipsoid plots for compounds 4 and 5 .

General Methods
NMR spectra for product characterization were recorded on a 200 MHz spectrometer using halogenated solvents stored on activated 4 Å molecular sieves, with TMS as an internal standard. In several cases extensive peak broadening was observed at room temperature and the spectra were recorded at high temperature in CDCl
2
CDCl
2
solvent. CDCl
3
was used in the spectra recorded at room temperature. For acetylation and transacetylation experiments carried out in NMR tubes in CD
3
CN, a 300 MHz spectrometer was used and the spectra were calibrated on the solvent signal. Electrospray mass spectra
(ES-MS) were obtained on an Electrospray Ionisation Time of Flight (ESI-TOF) spectrometer. HPLC analyses were performed on a liquid chromatograph fitted with a UV/VIS detector operating at 230 nm.
The analyses were carried out on a C18 column (25 cm × 4.6 mm I.D., particle size 5 μm) using MeCN as the mobile phase. A semipreparative C18 column (25 cm × 10 mm ID, particle size 5 μm) was used to obtain pure samples of 3 and 6 . Column chromatography was carried out on 230
–
400 mesh silica gel.
Melting points (uncorrected) were obtained in sealed evacuated capillaries.
Care was taken to minimize adventitious water while using caesium and tetramethylammonium fluoride, that were commercially available and used as received. HPLC grade MeCN stored on activated 4 Å molecular sieves was used for both the synthetic and the analytical acetylation runs. Adventitious water can account for partial hydrolysis of acetylated products and increased concentration of 1 , that were observed in some instances after very long reaction times.

Synthesis of compounds 2 – 7.
Compound 2 . A mixture of 1 (355 mg, 0.50 mmol) and CsF (270 mg, 1.77 mmol) in MeCN (15 mL) was refluxed for 1 h, then the temperature was lowered down to 45 °C and a solution of acetyl chloride
(50

L, 0.70 mmol) in MeCN (5 mL) was added. After 13 h of further stirring the mixture was subjected to chloroform-water work-up and to column chromatography (SiO
2
; hexane/ethyl acetate 9:1 as eluent) to obtain 2 (75 mg, 20% yield): mp 162-164 °C; MS (ES) + m/z 769.5 [M + NH
4
], 774.5 [M + Na]; 1 H
NMR, CDCl
2
CDCl
2
, 360 K: δ 1.24 (s, 18H), 1.26 (s, 9H), 1.31 (s, 9H), 2.43 (s, 3H), 3.77 (s, 2H), 3.86
(s, 2H), 4.51 (s, 4H), 4.55 (s, 2H), 4.63 (s, 2H), 6.87 (d, J = 2.1 Hz, 1H), 6.90 (d, J = 2.1 Hz, 1H), 6.96
(d, J = 2.1 Hz, 1H), 7.09 (d, J = 2.2 Hz, 1H), 7.24 (d, J = 2.1 Hz, 1H), 7.29 (d, J = 2.1 Hz, 1H), 7.34 (d,
J = 2.2 Hz, 1H), 7.42 (d, J = 2.1 Hz, 1H), 7.76 (s, 1H), 7.87 (s, 1H), 8.16 (s, 1H); 13 C NMR,
CDCl
2
CDCl
2
, 360 K: δ 20.5, 29.9, 31.2, 31.3, 31.5, 31.6, 33.9, 33.9, 34.3, 71.5, 71.7, 71.9, 72.8, 121.8
122.4, 123.6, 123.7, 123.8, 125.8, 126.1, 127.5, 127.5, 127.6, 127.9, 128.0, 128.7, 133.9.
Compound 3 . A mixture of 1 (709 mg, 1.00 mmol) and CsF (930 mg, 6.11 mmol) in MeCN (45 mL) was refluxed for 1 h, then the temperature was lowered down to 0 °C and a cold solution of acetyl chloride (150

L, 2.10 mmol) in MeCN (4 mL) was added. After 2 h of further stirring and the usual work-up, column chromatography (SiO
2
; CHCl
3 as eluent) afforded 3 (556 mg, 70% yield). An analytically pure sample was obtained by HPLC: MS (ES) + m/z 811.6 [M + NH
4
], 816.5 [M + Na]; 1 H
NMR, CDCl
3
: δ 1.23 (s, 18H), 1.27 (s, 18H), 1.80 (s, 6H), 3.76 (s, 4H), 4.33 (s, 4H), 4.67 (s, 4H), 6.66
(s, 2H), 7.05 (d, J = 2.1 Hz, 2H), 7.15 (d, J = 1.7 Hz, 2H), 7.19 (d, J = 2.1 Hz, 2H), 7.24 (d, J = 1.7 Hz,
2H); 13 C NMR, CDCl
3
, 298 K: δ 20.0, 30.7, 31.3, 31.5, 34.0, 34.4, 67.6, 71.1, 123.2, 124.3, 126.0,
126.5, 127.2, 128.1, 129.3, 132.1, 142.8, 144.9, 148.6, 150.8, 169.5.
Compound 4 . A mixture of 1 (355 mg, 0.50 mmol) and K
2
CO
3
(280 mg, 2.00 mmol) in MeCN (15 mL) was refluxed for 20 min, then the temperature was lowered down to 45 °C. A solution of acetyl chloride
(100

L, 1.40 mmol) in MeCN (5 mL) was rapidly added and the reaction was quenched by addition of water after 5 min. After the usual work-up the mixture was subjected to column chromatography (SiO
2
;

CHCl
3
as eluent) to give 4 (125 mg, 32% yield); MS (ES) + m/z 811.6 [M + NH
4
], 816.5 [M + Na]; 1 H
NMR, in CDCl
2
CDCl
2
at 350 K: δ 1.22 (s, 18H), 1.30 (s, 18H), 2.35 (s, 6H), 3.75 (s, 4H), 4.44 (s, 4H),
4.54 (s, 4H), 6.90 (d, J = 2.3 Hz, 2H), 7.08 (d, J = 2.3 Hz, 2H), 7.17 (s, 2H), 7.33 (d, J = 2.3 Hz, 2H),
7.34 (d, J = 2.3 Hz, 2H). 13 C NMR, in CDCl
2
CDCl
2
at 350 K: δ20.4, 30.1, 31.3, 31.6, 33.9, 34.3, 71.5,
72.7, 121.7, 123.8, 125.7, 127.7, 128.1, 128.4, 133.4, 142.3, 145.7, 148.7, 152.1, 169.4.
Compound 5 . A mixture of 3 (355 mg, 0.50 mmol) and CsF (473 mg, 3.11 mmol) in MeCN (15 mL) was refluxed for 1 h, then the temperature was lowered down to 45 °C and a solution of acetyl chloride
(71

L, 1.00 mmol) in MeCN (5 mL) was added. After 2 h of further stirring and heating and the usual work-up, the residue was treated with EtOAc. The undissolved material, consisting in 7 , was removed, while the filtrate was subjected to column chromatography (SiO
2
, eluent: CHCl
3
) and gave 5 (180 mg,
45% yield) after recrystallization from acetone: mp 154-157 °C; MS (ES) + m/z 811.6 [M + NH
4
], 816.5
[M + Na]; 1 H NMR, CDC
3
: δ 1.26 (s, 18H), 1.27 (s, 18H), 1.79 (s, 6H), 3.73 (s, 2H), 3.83 (s, 2H), 4.42
(s, 4H), 4.57 (s, 4H), 7.01 (d, J = 2.4 Hz, 2H), (s, 2H), 7.20 (d, J = 2.3 Hz, 2H), 7.22 (d, J = 2.3 Hz, 2H),
7.26(d, J = 2.4 Hz, 2H), 7.58 (s, 2H); 13 C NMR: δ 20.0, 30.8, 31.3, 31.5 ,32.7, 34.0, 34.4, 69.2, 70.0,
123.2, 123.8, 126.5, 127.1, 127.7, 128.1, 128.8, 131.7, 143.0, 145.6, 148.8, 149.9, 169.3.
Compound 6 . An analytically pure sample of 6 was obtained through HPLC; MS (ES) + m/z 857.56 [M
+ Na], 873.5[M + K]; 1 H NMR, CDCl
2
CDCl
2
, 343 K: δ 1.26(s, 9H), 1.29 (s, 9H), 1.29 (s, 18H), 1.53 (s,
3H), 1.73 (s, 3H), 1.84 (s, 3H), 3.65 (s, 2H), 3.72 (s, 2H), 4.26 (s, 2H), 4.31 (s, 2H), 4.36 (s, 2H), 4.62
(s, 2H), 6.92 (d, J = 2.4 Hz, 1H), 7.15-7.27 (superposed, 7H); 13 C NMR, CDCl
2
CDCl
2
, 343 K: δ 19.0,
20.0, 20.2, 30.2, 31.4, 33.0, 33.9, 34.3, 34.4, 67.4, 67.8, 69.6, 122.5, 123.9, 125.0, 125.7, 125.9, 127.2,
127.4, 127.6, 128.0, 128.2, 129.0, 129.4, 130.0, 131.6, 132.4, 133.5, 142.5, 143.2, 145.5, 148.6, 148.8,
149.1, 150.3, 151.2, 168.9, 169.1, 169.3.
Compound 7 . A mixture of 1 (200 mg, 0.28 mmol) and K
2
CO
3
(323 mg, 2.34 mmol) in MeCN (10 mL) was stirred for 40 min at 50°C. The temperature was then lowered down to 30 °C and a solution of acetyl chloride (160  L, 2.24 mmol) in MeCN (5 mL) was added. The mixture was stirred for further 2

days then was subjected to the usual work-up. A recrystallization from acetone gave pure 7 (193 mg,
78% yield); mp > 350 °C; MS (ES) + m/z 895.5 [M + Na]; 1 H NMR, CDCl
2
CDCl
2
, 360 K: δ 1.29 (s,
36H), 1.71 (s, 12H), 3.60 (s, 4H), 4.28 (s, 8H), 7.18 (d, J = 2.3 Hz, 4H), 7.23 (d, J = 2.3 Hz, 4H); 13 C
NMR: CDCl
2
CDCl
2
, 360 K: δ 20.1, 31.4, 32.7, 34.4, 68.6, 126.2, 127.8, 129.7, 132.6, 145.6, 148.8,
169.0.

DINOS51M.501 200 MHZ 360K TCE t -Bu t -Bu
O
OAc
OH
OH
O
OH t -Bu
2 t -Bu in CDCl
2
CDCl
2
at 360 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinos51m
501
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 200.1289424 MHz
:
:
:
:
:
0
100
3300.46 Hz
: 2229.00 Hz
: 200.1322429 MHz
:
16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2609.12 Hz
1.4997850 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS
SPWIDTH :
DDATE :
ATIME :
: DINOS51M.501
:
:
9614
0
3205.13 Hz
1905/Nov/02
18:38:30
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
(ppm)
3.5
3.0
2.5
2.0
1.5
1.0
DINOS51M.513 200MHZ 360K TCE MONOACETYL
0.5
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinos51m
513
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
:
:
:
:
50.3198866 MHz
2
3464
8529.41 Hz
3154.53 Hz
50.3284160 MHz
248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
1.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3381.84 Hz
1.3105860 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS
SPWIDTH :
DDATE :
ATIME :
: DINOS51M.513
: 32768
: 2
12500.00 Hz
1905/Nov/02
18:57:31
180 170 160 150 140 130 120 110 100
(ppm)
90 80 70 60 50 40 30 20

t -Bu t -Bu t -Bu
O
OAc
OAc
OH
O
OH t -Bu in CDCl
3
at 298 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinosfff
601
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 200.1300036 MHz
:
:
:
:
:
:
0
52
3300.46 Hz
2229.00 Hz
: 200.1333040 MHz
: 16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.20 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2340.92 Hz
1.4997770 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
: DINOSFFF.001
: 9614
0
3205.13 Hz
DDATE
ATIME
:
:
1906/Jan/13
15:33:43
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
(ppm)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
DINOSFFF.013 1000 ACCUMULI
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO :
:
: dinosfff
13
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
:
:
:
:
50.3199506 MHz
2
1003
8529.41 Hz
3154.53 Hz
50.3284800 MHz
248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.20 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3317.85 Hz
1.3105840 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
DDATE :
ATIME :
: DINOSFFF.013
: 32768
2
12500.00 Hz
1906/Jan/13
21:02:27
180 170 160 150 140 130 120 110 100
(ppm)
90 80 70 60 50 40 30 20

DINOS53D.501 350K 53 DIACETIL D 200MHZ t -Bu t -Bu
O
OAc
OH
OH
O
OAc t -Bu
4 t -Bu in CDCl
2
CDCl
2
at 350 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinos53d
501
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 200.1290538 MHz
:
:
:
:
:
:
0
54
3300.46 Hz
2229.00 Hz
: 200.1323542 MHz
: 16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2607.16 Hz
1.4997840 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS
SPWIDTH :
DDATE :
ATIME :
: DINOS53D.501
:
:
9614
0
3205.13 Hz
1905/Nov/05
18:24:31
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
(ppm)
3.5
3.0
2.5
2.0
1.5
1.0
DINOS53D.513 D 200 MHZ, 350 K
0.5
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinos53d
513
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
:
:
:
:
50.3199776 MHz
2
6075
8529.41 Hz
3154.53 Hz
50.3285070 MHz
248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.70 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3381.83 Hz
1.3105840 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS
SPWIDTH :
DDATE :
ATIME :
: DINOS53D.513
:
:
32768
2
12500.00 Hz
1905/Nov/05
20:41:42
190 180 170 160 150 140 130 120 110 100
(ppm)
90 80 70 60 50 40 30 20

DINOSE54.501 CLOROF 298 K 200 MHZ t -Bu t -Bu
O
OAc
OH
OAc
O
OH t -Bu
5 t -Bu in CDCl
3
at 298 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
:
DINOSE54
501
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 200.1300019 MHz
:
:
:
:
:
0
50
3300.46 Hz
: 2229.00 Hz
: 200.1333024 MHz
:
16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2341.70 Hz
1.4997770 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
: DINOSE54.501
: 9614
0
3205.13 Hz
DDATE
ATIME
:
:
1905/Nov/01
20:32:50
8.5
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
(ppm)
4.0
3.5
3.0
2.5
2.0
1.5
1.0
DINOSE54.513 DIACETIL E CLOR 298 K 200 MHZ
0.5
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinose54
513
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
:
:
:
:
50.3209258 MHz
2
35697
8529.41 Hz
3154.53 Hz
50.3294552 MHz
248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
1.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3317.77 Hz
1.3105590 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
DDATE :
ATIME
: DINOSE54.513
: 32768
:
2
12500.00 Hz
1905/Nov/02
09:37:29
180 170 160 150 140 130 120 110 100
(ppm)
90 80 70 60 50 40 30 20 10

DINOSGGG.343 t -Bu t -Bu
O
OAc
OAc
OAc
O
OH t -Bu
6 t -Bu in CDCl
2
CDCl
2
at 343 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinosggg
343
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
200.1299991 MHz
0
:
:
85
3300.46 Hz
: 2229.00 Hz
: 200.1332996 MHz
16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.20 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2605.21 Hz
1.4997770 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
: DINOSGGG.343
: 9614
0
3205.13 Hz
DDATE
ATIME
:
:
1906/Jan/14
14:06:24
8.0
7.5
7.0
6.5
6.0
5.5
5.0
4.5
4.0
(ppm)
3.5
3.0
2.5
2.0
1.5
1.0
0.5
DINOSGGG.113 17000 ACCUM 343 K TCE 200 MHZ
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
: dinosggg
113
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
:
:
:
:
:
:
:
:
:
50.3209230 MHz
2
17425
8529.41 Hz
3154.53 Hz
50.3294524 MHz
248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
1.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3381.00 Hz
1.3105590 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS
SPWIDTH
DDATE
ATIME
:
:
:
: DINOSGGG.113
: 32768
:
2
12500.00 Hz
1906/Jan/14
20:30:53
210 200 190 180 170 160 150 140 130 120 110
(ppm)
100 90 80 70 60 50 40 30 20 10

DINOSQ56.501 TCE 200 MHZ 360 K t -Bu t -Bu
O
OAc
OAc
OAc
O
OAc t -Bu
7 t -Bu in CDCl
2
CDCl
2
at 360 K
1 H, 200 MHz; 13 C, 50.3 MHz
*** Current Data Parameters ***
NAME
EXPNO
PROCNO
:
:
:
DINOSQ56
501
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 200.1300019 MHz
:
:
:
:
:
0
100
3300.46 Hz
: 2229.00 Hz
: 200.1333024 MHz
:
16.0150 ppm
9614
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
0.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
2606.97 Hz
1.4997770 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
: DINOSQ56.501
: 9614
0
3205.13 Hz
DDATE
ATIME
:
:
1905/Nov/01
17:36:37
8.0
7.0
DINOSQ56.513 TCE 360 K 200 MHZ
6.0
5.0
4.0
(ppm)
3.0
2.0
1.0
0.0
*** Current Data Parameters ***
NAME
EXPNO
PROCNO :
:
: dinosq56
513
1
*** Acquisition Parameters ***
BF1
DS
NS
O1
O2
SFO1
SW
TD
VD
: 50.3209258 MHz
:
:
:
:
:
2
7154
8529.41 Hz
: 3154.53 Hz
: 50.3294552 MHz
: 248.3940 ppm
32768
0.0000000 sec
*** Processing Parameters ***
LB
SI
:
:
1.00 Hz
16384
*** 1D NMR Plot Parameters ***
SR
AQ_time
:
:
3381.76 Hz
1.3105590 sec
*** Aspect 3000 Parameters ***
NM
TDSIZE
DSCANS :
SPWIDTH :
: DINOSQ56.513
: 32768
2
12500.00 Hz
DDATE
ATIME
:
:
1905/Nov/01
20:16:49
180 170 160 150 140 130 120 110 100
(ppm)
90 80 70 60 50 40 30 20

2
4
A
13 h
2 h
7
6
3
5
4
3
7
6
4
2
1
1
3
1
30 min
7
6 2
0 2 4 6 elution time (min)
8 10
F IGURE S1.
HPLC chromatograms showing the time-dependent composition of the reaction mixture obtained from 1 mole of 1 , 1.5 moles of AcCl and 3.5 moles of CsF, in MeCN at 50 °C.

F IGURE S2.
1 H NMR spectra at 298 K in CD
3
CN, signals of t -Bu groups. A) compound 3 ; B) taken after 2 min from the addition of excess K
2
CO
3
; C) taken after 15 h from the addition of K
2
CO
3
.

F IGURE S3.
1 H NMR spectra at 298 K in CD
3
CN, signals of t -Bu groups: A) compound 3 ; B) spectrum taken 5 min after the addition of excess KF; C) reaction mixture of spectrum B, taken after 15 min; D) reaction mixture of spectrum B, taken after 15 h.

F IGURE S4.
1 H NMR spectra in CD
3
CN, signals of t -Bu groups: A) compound 4 , at 298 K; B) spectrum taken 3 min after the addition of excess CsF, at 298 K; C) spectrum at 298K of the reaction mixture of spectrum B after heating 15 min at 330 K; D) spectrum at 330 K of the reaction mixture of spectra B and C, after further heating at 330 K (3 h).

F IGURE S5.
1 H NMR spectra in CD
3
CN, signals of t -Bu groups. The whole experiment was carried out at 298 K: A) compound 3 ; B) spectrum taken 2 min after the addition of excess
K
2
CO
3
; C), D), E), and
F) spectra taken 2 min, 13 min, 102 min and 169 min, respectively, after the addition of excess CsF to the reaction mixture of spectrum B.

Crystallographic Data Collection and Structure Determination.
The data for compounds 4 and
5 ·(CH
3
)
2
CO were collected at 100(2) K on a Nonius Kappa-CCD area detector diffractometer 1 using graphite-monochromated Mo-K  radiation (  = 0.71073 Å). The unit cell parameters were determined from ten frames, then refined on all data. The data (  - and  -scans) were processed with HKL2000.
2 The structures were solved by direct methods with SHELXS-97 and subsequent Fourier-difference synthesis and refined by full-matrix least-squares on F 2 with SHELXL-97.
3 No absorption correction was applied.
All non-hydrogen atoms were refined with anisotropic displacement parameters. The hydrogen atoms bound to O2 in 4 and to O6 and O7 in 5 ·(CH
3
)
2
CO were found on Fourier-difference maps and all the others were introduced at calculated positions; all were treated as riding atoms with a displacement parameter equal to 1.2 (OH, CH, CH
2
) or 1.5 (CH
3
) times that of the parent atom. One tertbutyl group in 4 is rotationally disordered over two positions which have been affected with 0.5 occupancy factors and refined with restraints on bond lengths and displacement parameters. The refinement of the structure of 4 was not quite satisfactory due to the the low quality of the crystals and hence the diffraction data, but the substitution pattern is however unambiguously determined.
The molecular plots were drawn with
SHELXTL.
4
Crystal data for compound 4 . C
50
H
64
O
8
, M = 793.01, monoclinic, space group C 2/ c , a = 26.437(3), b
= 9.3730(11), c = 19.0763(16) Å,

= 105.419(7)°, V = 4556.9(8) Å 3 , Z = 4, D c
= 1.156 g cm
–3
,

=
0.077 mm
–1
, F (000) = 1712. Refinement of 293 parameters on 4201 independent reflections out of
33323 measured reflections ( R int
= 0.079) led to R 1 = 0.131, wR 2 = 0.313, S = 1.122,
 max
= 0.80,
 min
= –0.52 e Å
–3
.
Crystal data for compound 5
·(CH
3
)
2
CO
. C
53
H
70
O
9
, M = 851.09, triclinic, space group P ī, a =
11.2074(5), b = 13.3796(10), c = 16.7503(11) Å,

= 81.543(4),

= 77.386(4),

= 89.998(4)°, V =
2423.1(3) Å 3 , Z = 2, D c
= 1.166 g cm
–3
,

= 0.078 mm
–1
, F (000) = 920. Refinement of 575 parameters on 9179 independent reflections out of 114247 measured reflections ( R int
= 0.040) led to R 1 = 0.043, wR 2 = 0.117, S = 1.000,
 max
= 0.16,
 min
= –0.23 e Å
–3
.

(1) Kappa-CCD Software ; Nonius BV: Delft, The Netherlands, 1998.
(2)
Otwinowski, Z.; Minor, W. Methods Enzymol . 1997 , 276 , 307.
(3)
Sheldrick, G. M. SHELXS-97 and SHELXL-97 ; University of Göttingen: Göttingen, Germany,
1997.
(4) Sheldrick, G. M. SHELXTL , version 5.1; Bruker AXS Inc.: Madison, WI, 1999.

F IGURE S6 . View of the X-ray crystal structure of compound 4 . Carbon-bound hydrogen atoms are omitted. Displacement ellipsoids are drawn at the 30% probability level. Only one position of the disordered tertbutyl group is represented. Symmetry code: ' = ½ – x , ½ – y , 1 – z .
F IGURE S7 . View of the X-ray crystal structure of compound 5 ·(CH
3
)
2
CO. Hydrogen atoms not involved in hydrogen bonds are omitted. Hydrogen bonds are drawn as dashed lines. Displacement ellipsoids are drawn at the 30% probability level.