A New Asymmetric Synthesis of (S)-Dolaphenine and Its Heteroaromatic Congeners Utilizing (+)-2-Hydroxy-3-pinanone and (−)-3-Hydroxy-2-caranone as Chiral …
(+)-2-Hydroxy-3-pinanone ((+)-HyPN,(+)-2a) and (−)-3-hydroxy-2-caranone ((−) 2b) were respectively converted to the corresponding Schiff bases 18a and 18b with 1-(2 thiazolyl) methylamine (17). Alkylation followed by removal of the chiral auxiliaries (+)-2a and (−)-2b afforded (S)-dolaphenine (10) as an optically pure form. The method was applied to the asymmetric synthesis of the dolaphenine analogs 27ad.