1995, Vol.68, No.4


Two types of catalysts, five-coordinate organotin bromides and tetraphenylstibonium bromide, similarly promoted the selective addition of tin enolates to the carbonyl moiety in α-halo ketones. The reaction with 2-chlorocyclohexanones and the enolates gave chlorohydrins bearing chloro- and hydroxyl groups in the cis-conformation. Chemoselective carbonyl addition to acyclic α-halo ketones was followed by effective cyclization to 2-(2-oxoethyl)oxiranes. The structural and bonding analogy of both catalysts may be responsible for the similar catalytic activities which induced the chemo- and stereoselective addition.