Synthesis of bicyclic cyclopentanols by photoreductive cyclization of .delta.,.epsilon.-unsaturated ketones
作者:D. Belotti、J. Cossy、J. P. Pete、C. Portella
DOI:10.1021/jo00372a018
日期:1986.10
Photoreductive cyclization of δ,ϵ-unsaturated ketones
作者:D. Belotti、J. Cossy、J.P. Pete、C. Portella
DOI:10.1016/s0040-4039(00)98759-8
日期:1985.1
Samarium(II) iodide-induced reductive cyclization of unactivated olefinic ketones. Sequential radical cyclization/intermolecular nucleophilic addition and substitution reactions
作者:Gary A. Molander、Jeffrey A. McKie
DOI:10.1021/jo00037a033
日期:1992.5
Samarium(II) iodide in the presence of HMPA effectively promotes the intramolecular coupling of unactivated olefinic ketones by a reductive ketyl-olefin radical-cyclization process. The reaction is quite general for the formation of 5- and 6-membered carbocycles and even provides modest yields in less facile cyclization processes as evidenced by the generation of methylcyclooctanol via an 8-endo cyclization. Sequential radical cyclization-intermolecular nucleophilic addition/substitution processes set the SmI2 reaction apart from its radical-chain, photochemical, and electrochemical counterparts. In addition to delineating the synthetic potential of this reaction, the role played by HMPA in enhancing SmI2 reactivity has been further refined, and a model correlating the high diastereoselectivity and product distribution in SmI2-promoted reductive coupling processes with HMPA concentration has been established.