Gold-Catalyzed Enantioselective Ring-Expanding Cycloisomerization of Cyclopropylidene Bearing 1,5-Enynes
نویسندگان
چکیده
An enantioselective ring-expanding cycloisomerization of 1,5-enynes bearing a cyclopropylidene moiety has been developed. This methodology provides a new approach to bicyclo[4.2.0]octanes, a structural motif present in many biologically active natural products.
منابع مشابه
Catalytic isomerization of 1,5-enynes to bicyclo[3.1.0]hexenes.
The cycloisomerization of 1,5-enynes catalyzed by cationic triphenylphosphinegold(I) complexes produces bicyclo[3.1.0]hexenes. Substitution at all positions of the 1,5-enyne is tolerated, leading to a wide range of bicyclo[3.1.0]hexane structures, including those containing quaternary carbons. Substrates containing a 1,2-disubstituted olefin undergo stereospecific cycloisomerization (cis-olefin...
متن کاملA gold-catalyzed unique cycloisomerization of 1,5-enynes: efficient formation of 1-carboxycyclohexa-1,4-dienes and carboxyarenes.
A novel Au-catalyzed migratory cycloisomerization strategy is advanced. Implementation of this strategy led to the development of a unique Au-catalyzed 1,5-enyne cycloisomerizatioin involving carboxy migration and Au-mediated C-C single bond formation. 1-Carboxycyclohexa-1,4-dienes and carboxyarenes can be prepared with good efficiency and with flexible substitution patterns.
متن کاملAsymmetric Au(i)-catalyzed synthesis of bicyclo[4.1.0]heptene derivatives via a cycloisomerization process of 1,6-enynes.
The enantioselective asymmetric gold-catalyzed cycloisomerization reactions of heteroatom tethered 1,6-enynes are conducted in the presence of a chiral cationic Au(i) catalyst ((R)-4-MeO-3,5-(t-Bu)(2)-MeOBIPHEP-(AuCl)(2)/AgOTf system) in toluene under mild conditions and lead to functionalized bicyclo[4.1.0]heptene derivatives in excellent enantiomeric excesses ranging from 90-98%.
متن کاملPalladium-catalyzed enantioselective cyclization of silyloxy-1,6-enynes.
Transition-metal-catalyzed cycloisomerization and cyclization reactions of enynes have emerged as powerful methods for the construction of heteroand carbocyclic compounds.1 More recently, enantioselective cycloisomerization of 1,6and 1,7-enynes has been employed in the preparation of enantioenriched 1,4-diene containing structures.2-4 Despite its potential utility, the related enantioselective ...
متن کاملAu- and pt-catalyzed cycloisomerizations of 1,5-enynes to cyclohexadienes with a broad alkyne scope.
We describe the development of gold- and platinum-catalyzed cycloisomerizations of 1,5-enynes. This catalytic process displays a wide alkyne scope and furnishes a range of highly functionalized 1,4- and 1,3-cyclohexadienes. In the case of 1-siloxy-1-yne-5-enes, the reactions are efficiently catalyzed by AuCl (1 mol %) at ambient temperature to afford siloxy cyclohexadienes or the corresponding ...
متن کامل