N-Heterocyclic Carbene Catalyzed Dynamic Kinetic Resolution of Pyranones
作者:Changgui Zhao、Fangyi Li、Jian Wang
DOI:10.1002/anie.201508205
日期:2016.1.26
The dynamickineticresolution of 6‐hydroxypyranones with enals or alkynals through an asymmetric redox esterification is catalyzed by a chiral N‐heterocyclic carbene. The resulting esters are obtained in good to high yields and with high levels of enantio‐ and diastereocontrol. The reaction products are further derivatized to obtain functionalized sugar derivatives and natural products.
Highly effective: We report herein the first and highly efficient totalsyntheses of norzoanthamine and zoanthamine in full detail, which involves stereoselective synthesis of the requisite triene for an intramolecular Diels–Alder reaction via three‐component coupling reactions, the intramolecular Diels–Alder reaction, and subsequent crucial bis‐aminoacetalization as the key steps.
A new and efficient synthesis of rubriflordilactone A has been realized. The key transformations include the following: (1) an intramolecular Prins cyclization to establish the seven-membered ring containing two contiguous stereocenters; (2) a Mukaiyama hydration/oxa-Michael cascade to construct the B-ring; and (3) an unprecedented stereocontrol intermolecular o-QM type [4 + 2]-cycloaddition to rapidly
实现了 rubriflordilactone A 的新型高效合成。关键的转化包括以下内容:(1)分子内Pris环化,建立含有两个连续立体中心的七元环; (2) Mukaiyama水合/oxa-Michael级联构建B环; (3)前所未有的立体控制分子间o -QM型[4+2]-环加成反应,快速组装rubriflordilactone A的核心结构。