Catalytic Enantioselective α‐Ethynylation of Oxindoles: Total Synthesis of (‐)‐Corynoxine, (‐)‐Isorhynchophylline, (‐)‐Aspidospermidine, and (‐)‐Limaspermidine
Abstract
Abstract The all‐carbon quaternary stereogenic center of oxindoles is a crucial structural element of a broad spectrum of indole alkaloids, imparting these molecules with rigid three‐dimensional configurations essential for their biological activities. Here, we present a catalytic asymmetric α‐ethynylation reaction of oxindoles taking advantage of the catalysis of a spiropyrrolidine amide (SPA) triazolium. This transformation enables the enantioselective construction of the C3 quaternary carbon stereocenter of oxindoles while introducing a versatile ethynyl functionality. Employment of this methodology has been demonstrated in the divergent total synthesis of indole alkaloids (‐)‐corynoxine, (‐)‐isorhynchophylline, (‐)‐aspidospermidine, and (‐)‐limaspermidine, featuring a protecting group‐dependent 1,6‐Michael addition or an aminolysis/1,6‐Michael addition sequence to generate two distinct types of spiro‐indoles, tailored for different late‐stage synthetic purposes.
Article Details
Authors (7)
Bao‐Kuan Guo
School of Pharmaceutical Sciences School of Chemistry and Chemical Engineering Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs State Key Laboratory of Synergistic Chem‐Bio Synthesis Shanghai Jiao Tong University Shanghai China
Yu‐Dong Zhang
State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China
Ju‐Song Yang
State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China
Jin‐Rui Tian
State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China
Xiao‐Ming Zhang
State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China
Fu‐Min Zhang
State Key Laboratory of Applied Organic Chemistry College of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China
Yong‐Qiang Tu
School of Pharmaceutical Sciences School of Chemistry and Chemical Engineering Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs State Key Laboratory of Synergistic Chem‐Bio Synthesis Shanghai Jiao Tong University Shanghai China