Asymmetric acetate aldol reactions in connection with an enantioselective total synthesis of macrolactin A

Article abstract of DOI:10.1016/S0040-4039(96)02055-2

Asymmetric aldol-like reactions of cinnamaldehyde, dienal 3 (fragment C7-C12 of macrolactin A), and dienal 4 (fragment C15-C24) with (i) chiral acetylthiazolidinethione-derived enolates, (ii) chiral boron enolates, and (iii) silyl enolates in the presence of chiral titanium-2,2'-dinaphthol complexes are compared. Use of the thiazolidinethiode auxiliary and TiCl₄ shows practical advantages; e.g., C5-C12 fragment 7 has been isolated enantiomerically pure in 74% yield. Copyright (C) 1996 Elsevier Science Ltd.