Tandem carbophilic addition- N-acyliminium ion cyclization for the synthesis of functionalized pyrrolo[2,1-a]isoquinolones: Key intermediates for the preparation of Erythrina-type alkaloids

Sequential carbophilic addition of organolithium reagents- N-acyliminium ion cyclization of N-phenenethylsuccinimide 3 yields pyrrolo[2,1-a]isoquinolones 1 in high yields, with the possibility of varying the substituent at C-10b by changing the organolithium. Application of this methodology to the c...

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Bibliographic Details
Published in:Tetrahedron letters 1996-10, Vol.37 (43), p.7841-7844
Main Authors: Manteca, Izaskun, Sotomayor, Nuria, Villa, María-Jesús, Lete, Esther
Format: Article
Language:English
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Summary:Sequential carbophilic addition of organolithium reagents- N-acyliminium ion cyclization of N-phenenethylsuccinimide 3 yields pyrrolo[2,1-a]isoquinolones 1 in high yields, with the possibility of varying the substituent at C-10b by changing the organolithium. Application of this methodology to the cis-norbor-5-en-2,3-dicarboximide 7 using a functionalized organolithium reagent, the 3-(2-trimethylsilyl-1,3-dithian-2-yl)propyllithium 11, followed by desilylation and subsequent retro-Diels-Alder reaction affords the α,β-unsaturated pyrroloisoquinolone 9b, immediate precursor of Erythrina-type alkaloids. Pyrrolo[2,1-a]isoquinolones 1 and 2 were synthetized by a tandem sequence from N-phenenethylimides and several organolithiums, including 11 (prepared by reductive lithiation).
ISSN:0040-4039
1873-3581
DOI:10.1016/0040-4039(96)01745-5