Sequential silylcarbocyclization/silicon-based cross-coupling reactions.
A sequential rhodium-catalyzed silylcarbocyclization of enynes parlayed with a palladium-catalyzed, silicon-based cross-coupling reaction has been developed for the synthesis of highly substituted cyclopentanes. 1,6-Enynes reacted with benzyldimethylsilane in the presence of rhodium catalysts to afford five-membered rings bearing a (Z)-alkylidenylbenzylsilyl group. A variety of substitution patterns and heteroatom substituents were compatible. The silylcarbocyclization in which an unsaturated ester participated was also achieved. The resulting alkylidenylsilanes underwent palladium-catalyzed cross-coupling using tetra-n-butylammonium fluoride. This cross-coupling reaction displayed a broad substrate scope. A wide variety of substitution patterns, electronic properties, and heteroatoms were compatible. All of the cross-coupling reactions proceeded in high yields under very mild conditions and with complete retention of double bond configuration, resulting in densely functionalized 3-(Z)-benzylidenecyclopentanes and heterocycles.
Denmark
Scott E
SE
Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. denmark@scs.uiuc.edu
Liu
Jack Hung-Chang
JH
D002384:Catalysis; D003500:Cyclization; D008745:Methylation; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry; D012821:Silanes / Q000737:chemistry; D012825:Silicon / Q000737:chemistry*
D012821:Silanes; D010165:Palladium; D012825:Silicon