An Efficient Synthesis of Arylcyclobutenes via Cross-Coupling of Aryl Halides with 1-(Tri-n-butylstannyl)cyclobutene

1-Tri-n-butylstannylcyclobutene, obtained from 1-bromocyclobutene by lithium/bromine exchange and transmetalation with chloro-tri-n-butylstannane, could be effectively converted with aryl halides into 1-arylcyclobutenes by the Stille cross-coupling procedure. Hetero-aryl halides like 2-bromopyridine and 2-iodothiophene were also successfully coupled, and in 1,3,5-tribromobenzene, 1,2,4,5-tetrabromobenzene and hexabromobenzene all bromine atoms could be exchanged.