Synfacts 2011(3): 0251-0251  
DOI: 10.1055/s-0030-1259566
Synthesis of Heterocycles
© Georg Thieme Verlag Stuttgart ˙ New York

Cross-Metathesis Strategy for Pyrrole Synthesis

Contributor(s): Victor Snieckus, Johnathan Board
S. Shafi, M. Kędziorek, K. Grela*
Polish Academy of Sciences, Warsaw and Warsaw University, Poland
Further Information

Publication History

Publication Date:
16 February 2011 (online)

Significance

Reported is the synthesis of pyrroles using a cross-metathesis strategy. The use of triphenylborate as a Lewis acid was necessary in order to decrease the interaction between the catalyst and the nitrogen atom. Its addition increased the yield of product and also greatly decreased the reaction time. A mechanism is proposed in which the cross-metathesis reaction is followed by a rapid intramolecular ring closure to form the pyrrole. This is supported by a reaction using 3,3-diethoxy-1-propene in place of the α,β-unsaturated carbonyl derivative, which allowed isolation of the diethyl acetal of the proposed intermediate.