Malonic acid esters of ans-1-substituted-3-trifluoromethyl-2-butene-1-
ols underwent stereoselective, SET induced cyclization reaction sequen
ce in the presence of iodine, potassium carbonate and quaternary ammon
ium salt. The allyl substituents of the starting materials influenced
the diastereoisomeric composition of the new products. (C) 1997 Elsevi
er Science Ltd.