Total Synthesis of Bafilomycin A1 Relying on Iterative 1,2-Induction in Acyclic Precursors
摘要:
The macrolide bafilomycin A(1) was synthesized starting from D-valine and D-mannitol as chiral progenitors of propionate units. Acyclic subunits corresponding to different parts of the molecule were constructed based on an iterative 1,2-asymmetric induction protocol as a distinctive feature of the synthesis. The assembly of two segments encompassing the entire carbon framework of the macrolide was achieved by using a Stille coupling. The resulting seco-ester was further manipulated to provide crystalline bafilomycin A(1) via a conventional carbodiimide-mediated Keck-type macrolactonization.
Total Synthesis of Bafilomycin A1 Relying on Iterative 1,2-Induction in Acyclic Precursors
摘要:
The macrolide bafilomycin A(1) was synthesized starting from D-valine and D-mannitol as chiral progenitors of propionate units. Acyclic subunits corresponding to different parts of the molecule were constructed based on an iterative 1,2-asymmetric induction protocol as a distinctive feature of the synthesis. The assembly of two segments encompassing the entire carbon framework of the macrolide was achieved by using a Stille coupling. The resulting seco-ester was further manipulated to provide crystalline bafilomycin A(1) via a conventional carbodiimide-mediated Keck-type macrolactonization.
Iterative Synthesis of Deoxypropionate Units: The Inductor Effect in Acyclic Conformation Design
作者:Stephen Hanessian、Navjot Chahal、Simon Giroux
DOI:10.1021/jo061098o
日期:2006.9.1
Conjugateaddition of lithium dimethylcuprate to acyclic α,β-unsaturated esters of varying lengths bearing terminal alkyl or phenyl groups leads to a preponderance of syn 1,3-adducts when one methyl is already present. Conversion to enoates, and iteration of cuprateadditions also favors syn adducts to give contiguous deoxypropionate units in a growing chain. The effect of end-group variation (Me,