Asymmetric Synthesis of the Fully Functional Macrolide Core of Salicylihalamide: Remote Control of Olefin Geometry during RCM
作者:Alois Fürstner、Oliver R. Thiel、Gaetano Blanda
DOI:10.1021/ol006646d
日期:2000.11.1
[GRAPHICS]A catalysis-based approach to the core region 24 of the antitumor agents salicylihalamides A and B is reported. Key steps are two asymmetric hydrogenations of beta -keto esters 13 and 16 catalyzed by [(R)-BINAP-RuCl2](2). NEt3 and an RCM-based macrocyclization effected by the NHC-containing ruthenium carbene 21. The stereochemical outcome of the tatter reaction is controlled by remote substituents on the phenolic OH group of the cyclization precursor 23.
Total Synthesis of (−)-Salicylihalamide
作者:Alois Fürstner、Thorsten Dierkes、Oliver R. Thiel、Gaetano Blanda
the catalyst which bears an imidazol-2-ylidene ligand. The EIZ ratio obtained in this macrocyclizationreaction was determined by the protecting groups at the remote phenolic OH group of the cyclization precursor. The elaboration of the resulting cycloalkene 37 into the final target involved a CrCl2-mediated synthesis of vinyliodide 49 which, after deprotection, did undergo a copper-catalyzed cross-coupling