Enantio-and diastereoselective stepwise cyclization of polyprenoids induced by chiral and achiral LBAs. A new entry to (-)-ambrox,(+)-podocarpa-8, 11, 13-triene …

…, H Ishibashi, H Yamamoto

Index: Ishihara, Kazuaki; Ishibashi, Hideaki; Yamamoto, Hisashi Journal of the American Chemical Society, 2002 , vol. 124, # 14 p. 3647 - 3655

Full Text: HTML

Citation Number: 85

Abstract

An enantio-and diastereoselective stepwise cyclization of polyprenoids induced by Lewis acid-assisted chiral Brønsted acids (chiral LBAs) and achiral LBAs is described. In particular, the absolute stereocontrol in the initial cyclization of polyprenoids to form an A-ring induced by chiral LBAs and the importance of the nucleophilicity of the internal terminator in polyprenoids for the relative stereocontrol in subsequent cyclization are demonstrated.(-)- ...