Electronic and Steric Control of Rates and Selectivities in Rhodium-Catalyzed [2+2+2] Cycloadditions for Constructing Fused Tricyclic Hydronaphthofurans: A Density Functional Theory Study.

Fused tricyclic hydronaphthofurans with multiple chiral centers are very important skeletons for constructing natural products; however, their synthesis is challenging, and a detailed understanding of the final formation mechanism remains elusive. In this work, density functional theory computations were employed to characterize rhodium-catalyzed [2+2+2] cycloaddition of enyne with terminal alkynes. The putative mechanism involves an initial ligand exchange, followed by oxidative cyclization, olefin insertion, and reductive elimination processes.