Synthesis of .gamma.- and .delta.-lactones by free-radical annelation of Se-phenyl selenocarbonates
作者:Mario D. Bachi、Eric Bosch
DOI:10.1021/jo00043a030
日期:1992.8
A general method for the synthesis of gamma- and delta-lactones through the intramolecular addition of alkoxycarbonyl radicals, formed by reaction of Se-phenylselenocarbonates with n-Bu3SnH, onto carbon-carbon multiple bonds is described. This free-radical cyclization is characterized by high regioselectivity favoring exo addition and by a high ratio of cyclization to reduction. Monocyclic, fused bicyclic, and spirocyclic lactones are formed in good to excellent yield. Use of allyltri-n-butyltin as a chain-transfer agent in the place of n-Bu3SnH affords the corresponding 3-butenyl lactones.
NOZAKI, KYOKO;OSHIMA, KOICHIRO;UTIMOTO, KIITIRO, BULL. CHEM. SOC. JAP., 63,(1990) N, C. 2578-2583
Facile Reduction of Dithiocarbonates Derived from Secondary Alcohols with<i>n</i>-Bu<sub>3</sub>SnH–Et<sub>3</sub>B and Synthesis of 2-Furanthiones and 2-Furanones by Intramolecular Addition of Alkoxythiocarbonyl Free Radicals to Acetylenic Linkages
作者:Kyoko Nozaki、Koichiro Oshima、Kiitiro Utimoto
DOI:10.1246/bcsj.63.2578
日期:1990.9
reduction of dithiocarbonates or thiocarbonates by n-Bu3SnH–Et3B easily gives the corresponding hydrocarbons. The intermediate alkoxythiocarbonyl radical equivalents are trapped by properly located carbon–carbon multiple bonds. The dithiocarbonates derived from either homopropargylic or homoallylic alcohols produce tetrahydrofuranones upon treatment with n-Bu3SnH–Et3B. Application of this new method