在25°C下于1小时内通过BF 3· Et 2 O在乙酸酐中的作用进行N-取代的2,3,7,7a-四氢-3a,6-环氧异吲哚-1-酮中的环氧基桥的反应通过S N 1机制。在第一步中形成的烯丙基型阳离子可通过在异吲哚体系中的C-5处添加乙酰氧基来稳定,得到5,6-二乙酰氧基-2,3,5,6的顺式和反式异构体的混合物,将7,7a-六氢异吲哚-1-酮在这些条件下经24小时芳构化,得到2,3-二氢-1H-异吲哚-1-酮。
Intra-molecular Diels–Alder reactions of citraconamic acids from furfurylamines and citraconic anhydride: effects of substitution in the furan ring on regioselectivity
作者:Rajappa Murali、H Surya Prakash Rao、Hans W Scheeren
DOI:10.1016/s0040-4020(01)00175-2
日期:2001.4
Regioselectivity in the intra-molecular Diels–Alder (IMDA) reaction of furfurylcitraconamic acids derived from N-benzylfurfurylamines and citraconic anhydride can be controlled by substituents located in the furan ring and by reaction conditions. Reactions conducted under kinetic conditions resulted in cycloaddition products having methyl and aminomethylene substituent in 1,3-relationship whereas under