Aza-Wittig Reaction of N-Vinylic Phosphazenes with Carbonyl Compounds. Azadiene-Mediated Synthesis of Isoquinolines and 5,6-Dihydro-2H-1,3-oxazines
摘要:
N-Vinylic phosphazenes 4 are obtained by reaction of phosphorus ylide 5 and nitriles 6. Aza-Wittig reaction of phosphazenes 4 with aldehydes leads to the formation of 2-azadienes 1, which are easily converted into isoquinolines 2. Reaction of conjugated phosphazenes 4 with ethyl glyoxalate affords 5,6-dihydro-2H-1,3-oxazines 9 in a regio- and stereoselective fashion, while heterodienes 1 react with ethyl glyoxalate and diethyl ketomalonate giving 1,3-oxazines 11 and 12.
[4+2] Cycloaddition Reactions of Neutral 2-Azadienes with Electron-deficient Dienophiles
作者:Francisco Palacios、Concepción Alonso、Gloria Rubiales、Cristina Tobillas、José María Ezpeleta
DOI:10.3987/com-03-s65
日期:——
A method for the preparation of functionalized tetrahydropyridine and triazine derivatives is described, based on aza Diels-Alder reaction of neutral 2-aza-1,3-dienes with electron-poor dienophiles as tetracyanoethylene and N-phenyl-1,2,4-triazoline-3,5-dione.
Cycloaddition Reactions of Neutral 2-Azadienes with Acetylenic Esters
A method for the preparation of functionalized polysubstituted dihydropyridine and pyridine derivatives is described, based on cycloaddition reactions of 2-aza-1,3-dienes with dimethyl acetylenedicarboxylate and ethyl propiolate.