Diastereodivergent and Enantioselective [4+2] Annulations of γ-Butenolides with Cyclic 1-Azadienes

Molecules

Chao Li¹  Kun Jiang¹  Ying-Chun Chen¹ 

[1] College of Pharmacy, Third Military Medical University, Chongqing 400038, China; E-Mail:

关键词: asymmetric organocatalysis;    Brønsted base;    cinchona alkaloids;    butenolides;    1-azadienes;    diastereodivergence;   

DOI  :  10.3390/molecules200813642

来源: mdpi

【 摘 要 】

An asymmetric annulation reaction of γ-butenolides and cyclic 1-azadienes containing a 1,2-benzoisothiazole-1,1-dioxide motif has been studied, proceeding in a tandem Michael addition-aza-Michael addition sequence. Endo-type cycloadducts bearing fused tetracyclic skeletons were isolated in fair yields and with high enantioselectivity (up to >99% ee) under the catalysis of modified cinchona alkaloid (DHQD)₂PHAL. Besides, exo-type diastereomers could be produced using β-isocupreidine (β-ICD) as the catalyst, though with moderate enantioselectivity.

【 授权许可】

CC BY   
© 2015 by the authors; licensee MDPI, Basel, Switzerland.