Enantioselective synthesis of 2-sulfenylated aldehydes: Alkylation of sulfenylated acetaldehyde SAMP-hydrazones
摘要:
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%.
Unusual two-bond13C,13C coupling constants in sulphones
作者:Christoph Rücker、Hans Fritz
DOI:10.1002/mrc.1260261213
日期:1988.12
structurally diverse sulphones. In open‐chain (single coupling path) sulphones this 2J coupling ranges from 5.5 to 27.2 Hz, while in cyclic (multiple coupling path) sulphones values ranging from 4.3 to 21.6 Hz are observed. Sulphides and sulphoxides do not exhibit a corresponding coupling of comparable magnitude. A positive sign for this coupling is derivedfrom the data of cyclic sulphones. Whereas substituents