Direct enolization chemistry of 7-azaindoline amides: A case study of bis(tetrahydrophosphole)-type ligands

TETRAHEDRON

卷:74

Article; Proceedings Paper

Li, Zhao¹  Noda, Hidetoshi¹  Kumagai, Naoya¹  Shibasaki, Masakatsu¹ 

[1] Inst Microbial Chem BIKAKEN, Shinagawa Ku, 3-14-23 Kamiosaki, Tokyo 1410021, Japan

关键词: Asymmetric catalysis;    Enolates;    Copper;    Aldol reaction;    Mannich reaction;   

DOI  :  10.1016/j.tet.2018.03.073

来源: Elsevier

【 摘 要 】

7-Azaindoline amides are particularly useful in direct enolization chemistry due to their facilitated enolization in soft Lewis acid/Bronsted base cooperative catalysis. The Cu(I) complex of (R,R)-Ph-BPE, a bis(tetrahydrophosphole)-type chiral bisphosphine ligand, exhibits consistently high catalytic performance and stereoselectivity irrespective of the nature of the alpha-substituent of the amides. Unexpectedly, however, alkyl-substituted bis(tetrahydrophosphole)-type ligands have substantially inferior catalytic performance. Evaluation of the optimized structures of Cu(I)/amide and Cu(l)/enolate complexes provided clues to dissecting the diverted reaction outcomes. (C) 2018 Elsevier Ltd. All rights reserved.

【 授权许可】

Free