Convenient Formation of 4-Hydroxyalk-2-en-1-one Functionality via A Knoevenagel-type Carbon Chain Elongation Reaction of Aldehyde with 1-Arylsulfinylalkan-2-one

Abstract

A highly functionalized four-carbon unit, 4-hydroxyalk-2-en-1-one functionality [R2CH(OH)CH=CHCOR1], was conveniently prepared by a reaction of an aldehyde (R2CH2CHO) with a 1-(arylsulfinyl)alkan-2-one [ArS(O)CH2COR1] in the presence of diethylamine (Knoevenagel condition). Other functional groups, such as carbonyl and hydroxy groups, in both of the alkyl chains (R1, R2) did not prevent this reaction. This reaction was used to conveniently prepare (+/-)-(11E)-13-hydroxy-10-oxooctadec-11-enoic acid (14), having cytotoxic activity, and its analogues from undec-10-enoic acid in good yield.