Aza-Wittig Reaction of <i>N</i>-Vinylic Phosphazenes with Carbonyl Compounds. Azadiene-Mediated Synthesis of Isoquinolines and 5,6-Dihydro-2<i>H</i>-1,3-oxazines
作者:Francisco Palacios、Concepción Alonso、Gloria Rubiales
DOI:10.1021/jo961664n
日期:1997.2.1
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.