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

ABSTRACT: An asymmetric annulation reaction of ?-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 ?-isocupreidine (?-ICD) as the catalyst, though with moderate enantioselectivity.

SUBMITTER: Li C

PROVIDER: S-EPMC6332167 | biostudies-literature | 2015 Jul

REPOSITORIES: biostudies-literature

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

Li Chao C Jiang Kun K Chen Ying-Chun YC

Molecules (Basel, Switzerland) 20150727 8

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 th ...[more]

PMID: 26225947

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