Synlett 2008(1): 37-40  
DOI: 10.1055/s-2007-992379
LETTER
© Georg Thieme Verlag Stuttgart · New York

A New Reagent System for Efficient Silylation of Alcohols: Silyl Chloride-N-Methylimidazole-Iodine

Agnieszka Bartoszewicza, Marcin Kaleka, Johan Nilssona, Renata Hiresovaa, Jacek Stawinski*a,b
a Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 10691 Stockholm, Sweden
b Institute of Bioorganic Chemistry, Polish Academy of Sciences, Noskowskiego 12/14, 61704 Poznan, Poland
e-Mail: js@organ.su.se;
Further Information

Publication History

Received 18 September 2007
Publication Date:
21 November 2007 (eFirst)

Abstract

It was found that reactions of alcohols with silyl chlorides in the presence of N-methylimidazole were significantly accelerated by the added iodine, and on this basis a general, and high yielding method for efficient silylation of primary, secondary, and tertiary alcohols was developed.

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11

General Procedure for the Preparative Silylation of Alcohols Listed in Table 1: An alcohol (1.0 mmol), N-methylimidazole (3.0 mmol) and iodine (2.0-3.0 mmol) were dissolved in an appropriate, anhyd solvent (3 mL, Table [1] ). A silyl chloride (TBDMSCl, TBDPSCl or TIPSCl; 1.1 mmol) was added and the reaction mixture was stirred at r.t. until the complete disappearance of the starting material (TLC analysis). The solvent was evaporated, the residue dissolved in EtOAc and washed with concd aq Na2S2O3. The organic phase was dried over anhyd Na2SO4 and evaporated. The products were purified by silica gel column chromatography (CH2Cl2-MeOH, 100:0 → 95:5, Table [1] entries 1, 3 and 7; pentane-EtOAc, 10:0 → 9:1, Table [1] entries 2, 4-6, 8-10). The synthesized compounds were fully characterized with 1H and 13C NMR and HRMS.