Fleming−Tamao Oxidation and Masked Hydroxyl Functionality: Total Synthesis of (+)-Pramanicin and Structural Elucidation of the Antifungal Natural Product (−)-Pramanicin
作者:Anthony G. M. Barrett、John Head、Marie L. Smith、Nicholas S. Stock、A. J. P. White、D. J. Williams
DOI:10.1021/jo9905672
日期:1999.8.1
The total synthesis of (+)-pramanicin (41b) is reported, thereby establishing the relative and absolute stereochemistry of the naturally occurring antifungal agent. The key steps involve (i) conjugate addition of the diethyl((diethylamino)diphenylsilyl)zincate to a suitably protected gamma-lactam 3 and quenching of the resultant enolate with the alpha,beta-unsaturated gamma,delta-epoxy aldehyde 2 (X = H), (ii) Ni(acac)(2)-catalyzed hydroxylation of a beta-dicarbonyl array, and (iii) Fleming-Tamao oxidation to reveal the masked C-3 hydroxyl group.
Total synthesis of (+)-pramanicin and stereochemical elucidation of the natural product
作者:Anthony G. M. Barrett、Marie L. Smith、Nicholas S. Stock
DOI:10.1039/a807988i
日期:——
Total synthesis of (+)-pramanicin is achieved through a ‘one pot’ Michael addition of an aminosilyl zincate species to an α,β-unsaturated lactam and quenching of the resultant enolate with an α,β-unsaturated γ,δ-epoxy aldehyde.