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Nazarov Cyclization and Tandem [4 + 2]-Cycloaddition Reactions of Donor–Acceptor Cyclopropanes
The development of aryl vinyl/divinyl donor–acceptor cyclopropanes (DACs) as novel Nazarov cyclization (NC) precursors is described. The 1,3-zwitterion, generated from DACs embedded in the divinyl framework, acts as a pentadienyl cation, a requisite for Nazarov cyclization. A cyclic allyl cation in...
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Published in: | Organic letters 2017-09, Vol.19 (17), p.4500-4503 |
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Main Authors: | , , , |
Format: | Article |
Language: | English |
Citations: | Items that this one cites Items that cite this one |
Online Access: | Get full text |
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Summary: | The development of aryl vinyl/divinyl donor–acceptor cyclopropanes (DACs) as novel Nazarov cyclization (NC) precursors is described. The 1,3-zwitterion, generated from DACs embedded in the divinyl framework, acts as a pentadienyl cation, a requisite for Nazarov cyclization. A cyclic allyl cation in the course of NC was trapped with external nucleophiles to provide an interrupted NC product. Indeed, an allyl cation in this reaction is analogous to a 1,4-zwitterion that on reaction with dipolarophiles provided an easy access to substituted pyrans with excellent yield and diastereoselectivity via NC followed by a formal [4 + 2] cycloaddition. |
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ISSN: | 1523-7060 1523-7052 |
DOI: | 10.1021/acs.orglett.7b02061 |