A Facile Synthesis of N-Alkoxycarbonyl Aziridines from Olefins Bearing Two Geminal Electron-Withdrawing Groups
作者:Stefania Fioravanti、Alberto Morreale、Lucio Pellacani、Paolo A. Tardella
DOI:10.1055/s-2001-17707
日期:——
Nosyloxycarbamates react with unsaturated β-dicarbonyl compounds at room temperature in the presence of calcium oxide to give N-alkoxycarbonyl aziridines in high yield.
Base-induced reactions of 1-(phenylsulfonyl)-2-methylene-3-bromopropane (4) with 2-(phenylsulfonyl)-2-cycloalkenones 8a-d were investigated with the ultimate purpose to develop a route leading to bicyclic conjugated enediones. Low-temperature, fast-quenched reactions led generally to open-chain adducts, while increase of temperature and addition of HMPA resulted in subsequent ring closure by a tandem Michael-S(N)2 process. The stereochemical features of the bicyclo[3.3.0]octanes 11 and 12, bicyclo[4.3.0]nonanes 18 and 19, bicyclo[5.3.0]decanes 22 and 23, and bicyclo[6.3.0]-undecanes 26-28 thus obtained have been determined. Ozonolysis and silica-induced elimination of the tertiary phenylsulfonyl group converted stereoselectively the above products into the desired enediones: pentalenedione 29, indenedione 30, azulenedione 32 and cyclopentacyclooctenedione 33, respectively.
WATANABE, MIKIO;SHIRAI, KOZO;KUMAMOTO, TAKANOBU, J. CHEM. SOC. JAP., CHEM. AND IND. CHEM., 1982, N 11, 1780-1784
A synthetic equivalent of the Nazarov reagent, the silyl derivative 2, able to undergo base-catalyzed double Michael addition reactions with α,β-unsaturated carbonyl compounds has been developed. The new reagent satisfactorily reacts with unsaturated indolo[2,3-a]quinolizidine lactams to give pentacyclic yohimbinone-type derivatives.
已开发出能够与α,β-不饱和羰基化合物进行碱催化的双迈克尔加成反应的纳扎罗夫试剂的甲硅烷基衍生物2的合成等价物。该新试剂可与不饱和吲哚并[2,3- a ]喹啉嗪内酰胺反应,生成五环育亨宾酮型衍生物。
Chemoselective Epoxidation of Electron Deficient Enones with Iodosylbenzene
作者:Thomas R. Pettus、Kevin M. McQuaid
DOI:10.1055/s-2004-832814
日期:——
The epoxidation of electron deficient olefins is demonstrated with PhIO and an assortment of enones.