文摘
An efficient and practical method has been developed for the synthesis of trans-4,5-disubstituted 3-carboxy-4,5-dihydropyrroles via an intramolecular iminium ion cyclization reaction of readily accessible Baylis鈥揌illman derivatives and aldehydes in moderate to high yield. These new dihydropyrroles could be easily converted to pyrroles or pyrrolidines.