Efficient synthesis of chrysanthemate precursor from chiral p-tolyl β-(trimethylsilyl)ethyl sulfoxide
Abstract
Reaction of α-lithio-β-silylethyl sulfoxide with ethyl 4-bromo- or 4-chloro-4-methylpent-2-enoate gives the cyclopropanecarboxylate as a single diastereomer which is converted to (1R)-trans-2-formyl-3,3-dimethylcyclopropanecarboxylate in high overall yield.