[1-(Phenylseleno)alkyl]stannanes-mixed selenium/tin analogs of acetals: preparation from alpha-hydroxystannanes and use for generating selenium-stabilized carbanions.

Selenium-stabilized carbanions are available by a route that does not involve acid-catalyzed formation of selenoacetals. Aldehydes are converted first into alpha-hydroxystannanes and then into alpha-(phenylseleno)stannanes. Treatment with BuLi affords selenium-stabilized carbanions by preferential Sn/Li exchange.