A general method for the synthesis of azetidin-2-ones from 1, 3-dioxin-4-ones is described. The method consists of 1) the formatin of β-ketocarboxamides, 2) their reduction to 3-hydroxycarboxamides, 3) mesylationg, and 4) base-mediated cyclization of 3-mesyloxycarboxamides to the final azetidinones. Stereochemical demand in the cyclizatino step has been clarified by using 5, 6-tri- and -tetramethylene derivatives of 2, 2-dimethyl-1, 3-dioxin-4-one. Microbiological reduction of the acetoacetamides by baker's yeast gave (S)-3-hydroxybutanamides of ≥98% optical purity, whose cyclization afforded (R)-4-methylazetidin-2-ones.
An efficient and rapid synthesis of β-carboxamide derivatives using 2,2-dimethyl-2H,4H-1,3-dioxin-4-ones by microwave irradiation
作者:Bruhaspathy Miriyala、John S. Williamson
DOI:10.1016/j.tetlet.2003.08.118
日期:2003.10
A general, efficient and rapidmethod for the synthesis of various β-carboxamide derivatives using microwaveirradiation is described. Excellent isolated yields were obtained in very short reaction times when conventional heating was replaced by microwaveirradiation.
Regioselective Oxygenations of <i>S</i>-<i>Trans</i> Dienes, Silyl Dienol Ethers (SDEs), by Triphenyl Phosphite Ozonide (TPPO) and Its Mechanistic Study
作者:Atsushi Mori、Manabu Abe、Masatomo Nojima
DOI:10.1021/jo015562v
日期:2001.5.1
The direct oxygenation of s-trans dienes, silyl dienol ethers (SDEs) 2, by triphenyl phosphite ozonide (TPPO) has been examined in detail. The regioselective oxygenation was found to give hydroperoxide 3, alcohol 4, ketone 5, dimer 6, and peroxy phosphate 7 with concomitant formation of triphenyl phosphate 8 and diphenyl trimethylsilyl phosphate 10. The formation of peroxy phosphate 7 was found for
A new method for the synthesis of dioxolenones the carboxylation of ketone enolates with anisyl cyanoformate
作者:Kevin E Henegar、Jeffrey D Winkler
DOI:10.1016/s0040-4039(00)95908-2
日期:1987.1
depends on the availability of the requisite functionalized dioxolenones. We report herein a general approach to the preparation of dioxolenones, via carboxylation of ketone enolates with anisyl cyanoformate and condensation of the resulting ketoesters with acetone.