A phosphine-catalyzed [4＋2] annulation of a-substituted allenoate with exocyclic alkene moiety of oxindoles or indan-1,3-diones has been developed. Thus, under the catalysis of PPh3 （20 mol%）, a series of spirooxin...A phosphine-catalyzed [4＋2] annulation of a-substituted allenoate with exocyclic alkene moiety of oxindoles or indan-1,3-diones has been developed. Thus, under the catalysis of PPh3 （20 mol%）, a series of spirooxindole- or spiroindan-1,3-dione-cyclohexenes have been obtained in moderate to excellent yields and regioselectivity from the annulations of a-methyl allenoates with 3-methyleneoxindoles or 2-methyleneindan-1,3-diones. This method offers an easy access to structurally novel spirocyclohexenes.展开更多
基金Financial support from the Fundamental Research Funds for the Central Universities （No. KYZ201749） and the National Natural Science Foundation of China （Nos. 21272119, J1103306） are gratefully acknowledged.
文摘A phosphine-catalyzed [4＋2] annulation of a-substituted allenoate with exocyclic alkene moiety of oxindoles or indan-1,3-diones has been developed. Thus, under the catalysis of PPh3 （20 mol%）, a series of spirooxindole- or spiroindan-1,3-dione-cyclohexenes have been obtained in moderate to excellent yields and regioselectivity from the annulations of a-methyl allenoates with 3-methyleneoxindoles or 2-methyleneindan-1,3-diones. This method offers an easy access to structurally novel spirocyclohexenes.
