ENANTIOSELECTIVE SYNTHESIS OF 2-SULFENYLATED ALDEHYDES - ALKYLATION OF SULFENYLATED ACETALDEHYDE SAMP-HYDRAZONES

A practical and efficient enantioselective synthesis of 2-sulfenylated aldehydes (S)-6 is described, based on the alpha-alkylation of sulfenylated acetaldehyde SAMP hydrazones (S)-4, easily prepared from bromoacetaldehyde diethyiacetal 1, thiols and (S)-1-amino-2-methoxymethyl-pyrrolidine (SAMP). A chemoselective oxidative cleavage of the intermediate SAMP hydrazones (S,S)-5 with ozone gives rise to the title compounds (S)-6 in good overall yields and high enantiomeric excesses of up to 97%.