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Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
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Unified Strategy for the Concise Total Syntheses of All Six 3″-O-Acyl Quercitrins Based on Regioselective Acylation
Mari Tanikawa1, Toshihiro Ishida2, Yuki Nakamura1
1Laboratory of Organic Chemistry for Drug Development and Medical Research Laboratories, Department of Pharmaceutical Sciences, Kitasato University, Tokyo 108-8641, Japan.
Abstract:
The naturally occurring 3″-O-acylquercitrin family exhibits a range of biological activities with significant potential health and medical benefits. Herein, we present a unified strategy for concise total syntheses of all six known 3″-O-acylquercitrin natural products─namely, 3″-O-galloylquercitrin, 3″-O-(E)-cinnamoylquercitrin, 3″-O-(E)-coumaroylquercitrin, 3″-O-(E)-feruloylquercitrin, 3″-O-acetylquercitrin, and 3″-O-tigloylquercitrin─based on regioselective acylation of carbohydrates catalyzed by N-methylimidazole-containing boronic acid. The core advancement in this approach is a late-stage catalytic regioselective functionalization of a common synthetic intermediate, enabling efficient access to the natural products.
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