- Nazarov Cyclization and Tandem [4 + 2]-Cycloaddition Reactions of Donor-Acceptor Cyclopropanes
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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.
- Sudhakar, Gangarajula,Mahesh,Phani Babu Vemulapalli,Nanubolu, Jagadeesh Babu
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- Palladium-catalyzed silylene-1,3-diene [4 + 1] cycloaddition with use of (aminosilyl)boronic esters as synthetic equivalents of silylene
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(Chemical Equation Presented) Silylboronic esters bearing a dialkylamino group on the silicon atoms reacted with 1,3-dienes in the presence of a palladium catalyst to give silacyclopent-3-enes (i.e., 2,5-dihydrosiloles) in high yields via efficient silyle
- Ohmura, Toshimichi,Masuda, Kohei,Takase, Ichiro,Suginome, Michinori
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supporting information; experimental part
p. 16624 - 16625
(2010/02/16)
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- EFFICIENT PREPARATION OF POLYSUBSTITUTED 1,3-DIENES FROM α,α'-DIKETO SULFIDES
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A series of polysubstituted 1,3-dienes were prepared in good overall yields in three steps starting from readily accessible α,α'-diketo sulfides.
- Nakayama, Juzo,Machida, Haruki,Saito, Ryuji,Akimoto, Keiichi,Hoshino, Masamatsu
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p. 1173 - 1176
(2007/10/02)
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