A cationic rhodium(I)/(R)-tol-binap complex catalyzed the cross-cyclotrimerization of silylacetylenes R1C竕｡CH (R1 = Me3Si, Et3Si, PhCH2SiMe2), di-tert-Bu acetylenedicarboxylate, and enamides R2CH:CHCONR3R4 [R2 = H, Me, Et, n-Pr, i-Pr, Ph; R3 = R4 = Me, n-Bu; R3 = Me, R4 = MeO, Ph; R3R4 = (CH2)4] with excellent chemo-, regio-, and enantioselectivities to give the corresponding substituted cyclohexadienes I. Unsym. alkynoates can also be employed in place of di-tert-Bu acetylenedicarboxylate for this process, but with reduced chemoselectivity. [on SciFinder(R)]
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