The reaction of trialkylvinylborates with aldehydes as applied to syntheses of 1,3-alkanediols, 1-chloro-3-heptanol and a cyclopropane derivative

Abstract

Treatment of R'CHO with Li[R3BCHCH2] gives an adduct which is believed to be R2BCHR-CH2-CH(OLi)R' (2) or its borate form (3). Oxidation of the adducts with alkaline hydrogen peroxide gives ca. 1:1 mixture of diastereomeric 1,3-alkanediols in good yields. On the other hand, the reaction of BrMg[R3BCHCH2] with R'CHO affords less satisfactory results. Successive treatment of 2 (R = n-Bu, R' = H) with PCl5 and alkaline H2O2 gives HOCHBu-CH2-CH2Cl (6). Treatment of Et2BCHEt-CH2-CHCl-Ph with NaOH aq produces l-ethyl-2-phenylcyclopropane 7.