PRODUCTION OF CYCLOPENTENOL DERIVATIVE

摘要

PURPOSE:To easily obtain the subject compound useful as an intermediate for insecticides by reaction between a cyclopentenolone derivative, titanium tetrachloride, zinc, dibromomethane or diiodomethane. CONSTITUTION:The objective compound of formula II can be obtained by reaction in an organic solvent (e.g. THF) at -40 to 50 deg.C between (A) a compound of formula I (R1 is 2-propenyl or 2-propynyl; A is protecting group for OH), (B) 0.5-5mol permol of the component A of titanium tetrachloride, (C) 2-50mol permol of the component A of zinc and (D) 1-10mol permol of the component B of dibromomethane or diiodomethane. The compound of the formula II is e.g. (S)-2-methyl-4-methylidene-3-(2-propenyl)-1-trimethylsilyloxy-2-cyclop entene.