[3+2]-annulation reaction in the presence of a base. Compounds 6 were easily converted to 2-substituted cyclopent-2-en-1-ones by deethoxycarbonylation. An application of the annulation to synthesis of cis-jasmone is also described.
3-乙
氧基羰基-2-
丙烯(三
苯基)
亚膦酸酯(2)与
乙二醛一
水合物(5)反应,在[3 + 2]-环化反应中,生成2-取代的5-乙
氧基羰基环戊-2-
烯-1-
酮(6)。基地的存在。化合物6通过
脱乙
氧基羰基化容易地转化为2-取代的环戊-2-
烯-1-
酮。还描述了该成环法在顺式-
茉莉酮合成中的应用。