| Abstract
| - A novel methodology for the deprotonation of a methyl group on silicon has been developed. Thisnewly developed α-lithiation protocol is based on the intramolecular pyridyl group coordination tostabilize the α-silyl carbanion together with the inherent silicon α effect. It was found that thedeprotonation (t-BuLi/Et2O/−78 °C) occurs with 2-pyridyltrimethylsilane but not with other relatedsilanes such as phenyltrimethylsilane, 3-pyridyltrimethylsilane, and 4-pyridyltrimethylsilane. Itseems that this deprotonation proceeded through the agency of the complex-induced proximity effect(CIPE) of a 2-pyridyl group on silicon. 1H NMR analysis of (2-pyridyldimethylsilyl)methyllithiumrevealed the intramolecular coordination of a pyridyl group to lithium. (2-Pyridyldimethylsilyl)methyllithium was found to react with chlorosilanes, hydrosilanes, chlorostannanes, bromine, iodine,organic bromides, aldehydes, and ketones in good to excellent yields. The resultant adducts werefurther oxidized with H2O2/KF to give the corresponding alcohols in excellent yields. Thus, thistwo-step transformation provides an efficient method for the nucleophilic hydroxymethylation.
|
