A method for the synthesis of bicyclo[4.1.0]heptenes from 1,6-enynes through Pd-catalyzed cycloisomerization has been developed. N- and O-tethered 1,6-enynes were successfully transformed to their corresponding 3-aza- and 3-oxabicyclo[4.1.0]heptenes in reasonable-to-high yields using the catalysts [PdCl2(CH3CN)2]/P(OPh)3 or [Pd(maleimidate)2(PPh3)2] in toluene. The computational calculations using density functional theory indicate that [PdCl2{P(OPh)3}] in the oxidation state Pd(II) acts as the active catalyst species for the formation of 3-azabicyclo[4.1.0]heptenes through 6-endo-dig cyclization.

Palladium-catalyzed cyclization of cyclopropylsubstituted 1,6-enynes proceeded in two ways depending on the presence or absence of a leaving group. In the presence of the leaving group, 5.7-bicyclic trienes were obtained as the sole products; in the absence of the leaving group, monocyclic trienes were isolated.

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The cyclization of cyclopropyl‐substituted enynes proceeds in two ways depending on the presence or absence of a leaving group.