tert-Butyldimethylsilyl ether (TBS, TBDMS)

Protection :

Reagents

Solvents

Temperature

Time

Yield
Imidazole TBSCl

CH2Cl2

RT

5 min - 18 h

88-98 %

Imidazole, TBSCl

CH2Cl2

RT, 18 h, 97%

Imidazole, TBSCl

CH2Cl2

RT, 6 h, 90%

Imidazole, TBSCl

CH2Cl2

RT, 5 h, 88%

Imidazole, TBSCl

CH2Cl2

RT, 5 min, 98%
Imidazole TBSCl

CH2Cl2 DMF

RT

20 min

99 %

Imidazole, TBSCl

CH2Cl2, DMF

RT, 20 min, 99%
Imidazole TBSCl

DMF

0 °C - RT

6 h - 5 d

82-98 %

Imidazole, TBSCl

DMF

0 °C, 6 h, 82%

Imidazole, TBSCl

DMF

RT, ON, 98%

Imidazole, TBSCl

DMF

RT, 5 d, 82%
DMAP Imidazole TBSCl

CH2Cl2

0 °C - RT

60 min - ON

89-95 %

DMAP, Imidazole, TBSCl

CH2Cl2

RT, ON, 89%

DMAP, Imidazole, TBSCl

CH2Cl2

0 °C, 60 min, 95%
DMAP i-Pr2NEt TBSCl

CH2Cl2

0 °C - RT

3 h

88 %

DMAP, i-Pr2NEt, TBSCl

CH2Cl2

0 °C to RT, 3 h, 88%

"The following protection / deprotection sequence was due to a late deviation from the initial plan."
TBSCl

CH2Cl2

RT

60 min

100 %

TBSCl

CH2Cl2

RT, 60 min, 100%
2,6-Lutidine TBSOTf

CH2Cl2

0 °C

15 - 60 min

90-100 %

2,6-Lutidine, TBSOTf

CH2Cl2

0 °C, 60 min, 100%

2,6-Lutidine, TBSOTf

CH2Cl2

0 °C, 15 min, 90%

2,6-Lutidine, TBSOTf

CH2Cl2

0 °C, 40 min, 96%
2,6-Lutidine DMAP TBSOTf

CH2Cl2

0 °C

4 h

95 %

2,6-Lutidine, DMAP, TBSOTf

CH2Cl2

0 °C, 4 h, 95%
2,6-Lutidine TBSOTf

MeCN

RT

60 min

89 %

2,6-Lutidine, TBSOTf

MeCN

RT, 60 min, 89%
DMAP Et3N TBSCl

DMF

-20 °C - RT

2.5 - 3 h

69-71 %

DMAP, Et3N, TBSCl

DMF

-20 to -5 °C, 2.5 h, 69%

DMAP, Et3N, TBSCl

DMF

RT, 3 h, 71%
DMAP TBSCl

Pyr

RT

24 h

71 %

DMAP, TBSCl

Pyr

RT, 24 h, 71%
DMAP TBSCl N-Methylmorpholine

DMF

0 °C - RT

30 min

99 %

DMAP, TBSCl, N-Methylmorpholine

DMF

0 °C to RT, 30 min, 99%

Deprotection :

Reagents

Solvents

Temperature

Time

Yield
n-Bu4N+ F-

THF

0 - 70 °C

15 min - 16 h

70-100 %

n-Bu4N+ F-

THF

RT, 105 min, 85%

n-Bu4N+ F-

THF

0 °C, 15 min, 99%

n-Bu4N+ F-

THF

50 °C, 16 h, 95%

n-Bu4N+ F-

THF

RT, 7 h, 80%

n-Bu4N+ F-

THF

RT, 8 h, 92%

n-Bu4N+ F-

THF

50 °C, 60 min, 100%

n-Bu4N+ F-

THF

70 °C, 4 h, 70%

n-Bu4N+ F-

THF

RT, 3 h, 99%

n-Bu4N+ F-

THF

0 °C, 3 h, 100%

n-Bu4N+ F-

THF

0 °C to RT, 5 h, 97%

n-Bu4N+ F-

THF

RT, ON, 83%

n-Bu4N+ F-

THF

0 °C to RT, 3 h, 87%

n-Bu4N+ F-

THF

RT, 4 h, 93%

n-Bu4N+ F-

THF

RT, 60 min, 95%

"The product is also obtained by the degradation of natural azadirachtin."

n-Bu4N+ F-

THF

RT, 15 h, 97%
TASF

THF

RT

15 min - 48 h

80-94 %

TASF

THF

RT, 15 min, 94%

TASF

THF

RT, 48 h, 80%
HCl

H2O THF

0 °C - RT

30 min - 6 h

83-100 %

HCl

H2O, THF

RT, 6 h, 95%

HCl

H2O, THF

0 °C, 60 min, 83%

HCl

H2O, THF

RT, 3 h, 99%

HCl

H2O, THF

RT, 60 min, 100%

HCl

H2O, THF

RT, 3 h, 96%

HCl

H2O, THF

RT, 30 min, 88%
HCl

H2O MeOH

0 °C - RT

30 min - ON

83-99 %

HCl

H2O, MeOH

RT, 3 h, 89%

HCl

H2O, MeOH

RT, ON, 83%

HCl

H2O, MeOH

0 °C to RT, 30 min, 99%
Camphorsulfonic acid

MeOH

RT

60 min

90 %

Camphorsulfonic acid

MeOH

RT, 60 min, 90%
Camphorsulfonic acid

CH2Cl2 MeOH

RT

30 min

97 %

Camphorsulfonic acid

CH2Cl2, MeOH

RT, 30 min, 97%
Pyr.TsOH

EtOH

RT

ON

93 %

Pyr.TsOH

EtOH

RT, ON, 93%
BF3.OEt2

CH2Cl2

RT

14 h

89 %

BF3.OEt2

CH2Cl2

RT, 14 h, 89%
Pyr.HF

THF

RT

15 min - 3 h

76-91 %

Pyr.HF

THF

RT, 3 h, 91%

Pyr.HF

THF

RT, 15 min, 76%
AcOH

H2O

RT

60 min

100 %

AcOH

H2O

RT, 60 min, 100%
LiBF4

H2O MeCN

45-50 °C

31 h

98 %

LiBF4

H2O, MeCN

45-50 °C, 31 h, 98%
Pyr.HF

H2O MeCN

RT - 35 °C

34 h

85 %

Pyr.HF

H2O, MeCN

RT to 35 °C, 34 h, 85%
Et3NBn+ Cl- KF.2H2O

MeCN

60 °C

10 h

84 %

Et3NBn+ Cl-, KF.2H2O

MeCN

60 °C, 10 h, 84%