Calyculin synthetic studies. 2. Stereocontrolled assembly of the C(9)-C(13) dithiane and C(26)-C(37) oxazole intermediates
作者:Amos B. Smith、Brian A. Salvatore、Kenneth G. Hull、James J.-W. Duan
DOI:10.1016/s0040-4039(00)93480-4
日期:1991.9
C(26)-C(37) γ-amino acid/oxazole (+)-5, key building blocks for calyculin total synthesis, have been elaborated in homochiral form. Noteworthy features of the schemes include stereocontrolled generation of the C(36) steeocenter, exploiting a nucleophilic addition to the N-acyliminium cation derived from (+)-24, and amide formation via aluminum-mediated coupling of γ-lactam (−)-11 with amine (−)-12.
C(9)-C(13)二噻吩(+)- 2和C(26)-C(37)γ-氨基酸/恶唑(+)- 5(草木瓜总合成的关键组成部分)已在同手性形式。该方案的值得注意的特征包括C(36)立体中心的立体控制生成,利用亲核性添加至源自(+)- 24的N-酰基亚胺阳离子以及通过铝介导的γ-内酰胺(-)-形成的酰胺形成的酰胺。11与胺(-)- 12相同。