Two quaternary carbon centers are created in the title reaction to form fused dihydropyrans (see scheme). The same catalyst promotes the ortho functionalization of aryl ketones with 1,6‐enynes with excellent regio‐ and enantioselectivity. Z=amide, C(CO2Me)2, O; E=CO2Et, Ac; R1=Me, aryl, CO2Me; R2=Me; R3=Me, CO2Et.

We have achieved the first catalytic enantioselective synthesis of planar-chiral metacyclophanes by means of cationic rhodium(I)/(R)-H8-BINAP complex-catalyzed alkyne cyclotrimerization. This reaction represents a versatile new method for the preparation of planar-chiral [7]−[10]metacyclophanes.

A cationic rhodium(I)/(S)-Tol-BINAP complex was employed to catalyze an enantioselective intramolecular [2+2+2] cycloaddition of a trans enediyne leading to a C 2 -symmetric tricyclic dimethyl cyclohexadienedicarboxylate in 95% yield with 59% ee. A cationic rhodium(I)/(R)-H 8 -BINAP complex was employed to catalyze an intermolecular [2+2+2] cycloaddition of 1,6-diynes with dimethyl fumarate leading to C 2 -symmetric bicyclic dimethyl cyclohexadienedicarboxylates in 35-96% yields with ee values of 82-98%.

A cationic rhodium(i)/(R)-H(8)-BINAP or (R)-Segphos complex catalyzes an intramolecular [2 + 2 + 2] cycloaddition of unsymmetrical dienynes, leading to fused tri- and tetracyclic cyclohexenes bearing two tertiary or quaternary carbon centers in high yields with high enantio- and diastereoselectivity.

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