原卟啉IX二甲酯（1）与强亲二烯体丁炔二酸二甲酯（DMAD）进行〔4＋2〕环化加成生成相应的环A或环B二氢卟吩异构体。
Protoporphyrin IX dimethyl ester ( 1 ) reacted in a [ 4 + 2 ] cycloaddition with strongly activated dienophile & dimethyl acetylenedicarboxylate ( DMAD ) to give the corresponding chlorins with the ring A and B isomers .
亲二烯体