Enantioselective Synthesis of Pyrrole-Based Spiro- and Polycyclic Derivatives by Iridium-Catalyzed Asymmetric Allylic Dearomatization and Controllable Migration Reactions

• Published in: Angewandte Chemie International Edition Vol. 54; no. 29; pp. 8475 - 8479
• Main Authors: Zhuo, Chun-Xiang, Cheng, Qiang, Liu, Wen-Bo, Zhao, Qiang, You, Shu-Li
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 13.07.2015; WILEY‐VCH Verlag; Wiley; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Alkadienes - chemistry; Allyl Compounds - chemistry; asymmetric catalysis; Asymmetry; Catalysis; Chemistry; Chemistry, Multidisciplinary; dearomatization; Derivatives; enantioselectivity; iridium; Iridium - chemistry; Migration; Physical Sciences; Pyrroles; Pyrroles - chemistry; Science & Technology; Spiro Compounds - chemistry; Stability; Stereoisomerism; stereospecific migration; Synthesis; enantioselectivity; HYDROGENATION; ACTIVE (PI-ALLYL)IR COMPLEXES; ALKYLATION; dearomatization; asymmetric catalysis; iridium; FUNCTIONALIZATION; RESTING STATES; PD; SUBSTITUTIONS; REGIO; INTERMEDIATE; ALPHA-ALLYLATION; stereospecific migration
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201502259

The first highly diastereo‐ and enantioselective synthesis of five‐membered spiro‐2H‐pyrroles was achieved using an Ir‐catalyzed asymmetric allylic dearomatization reaction. The spiro‐2H‐pyrrole derivatives readily undergo a controllable and stereospecific allylic migration under acid catalysis, providing polycyclic pyrrole derivatives in excellent yields and ee values. Additionally, the novel Ir‐complex K1, derived from [Ir(cod)Cl]2 (cod=1,5‐cyclooctadiene) and N‐benzhydryl‐N‐phenyldinaphthophosphoramidite (BHPphos), showed excellent control of both diastereo‐ and enantioselectivities. It's all under control: The highly diastereo‐ and enantioselective synthesis of five‐membered spiro‐2H‐pyrroles was achieved using an Ir‐catalyzed asymmetric allylic dearomatization. The spiro‐2H‐pyrrole derivatives readily undergo a stereospecific allylic migration under acid catalysis, providing polycyclic pyrrole derivatives in excellent yields and ee values.