Abstract A novel approach to the synthesis of bicyclo[3.2.1]octanesystems is described. The key step involves the McMurry coupling of ketoaldehyde 7 which leads to the bridgehead dihydroxybicyclo [3.2. l] octane 8.
(Phenylsulfonyl)allenes as Substrates for Cycloaddition Reactions: Intramolecular Cyclizations onto Unactivated Alkenes
作者:Albert Padwa、Michael Meske、S. Shaun Murphree、Scott H. Watterson、Zhijie Ni
DOI:10.1021/ja00132a005
日期:1995.7
The reaction of a series of allyl-substituted bis(phenylsulfonyl)methanes or dimethyl malonates with 2,3-bis(phenylsulfonyl)-1,3-butadiene in the presence of base afforded alkenyl-substituted allenes in good yield. The reaction proceeds by initial attack of the soft carbanion onto the terminal position of the diene, and this is followed by PhSO(2)(-) elimination to give the phenylsulfonyl-substituted allene. Themal [2 + 2]-cycloaddition proceeded across the C-1-C-2 double bond of the allene with completely sterospecificity. Stepwise bonding prefers to occur in a 1,6-exo manner rather than in a 1,7-endo fashion. Substitution at the 7-position of the pi-bond causes a crossover in the regioselectivity of the [2 + 2]-cycloaddition process. All products can be rationalized by a mechanism which includes an initial carbon-carbon bond formation involving the central allene carbon to give a diradical intermediate. The product distribution is then determined by the substitution pattern of the alkene and the fate of the diradical intermediate.
Nasarow; Bergel'son, Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, 1960, p. 887,889; engl. Ausg. S. 826, 827
作者:Nasarow、Bergel'son
DOI:——
日期:——
Palladium-catalyzed cyclizations of bromodialkenyl ethers and amines
作者:L. Shi、C. K. Narula、K. T. Mak、L. Kao、Y. Xu、R. F. Heck
DOI:10.1021/jo00170a005
日期:1983.11
Mereshkowski, Justus Liebigs Annalen der Chemie, 1923, vol. 431, p. 238