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 totalsynthesis, 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.
Calyculin synthetic studies. 3. Enantiomeric purity determination for the C(26)–C(32) oxazole segment via the silks-odom 77Se NMR method
作者:Brian A. Salvatore、Amos B. Smith
DOI:10.1016/s0040-4039(00)76209-5
日期:1994.2
An improved preparation of the C(26)-C(32) oxazole subunit of calyculin A is described. The enantiomeric purity was determined via the exceptionally sensitive Silks-Odom method, which can probe remote stereocenters by Se-77 NMR analysis.