Computational Study on the Co-Mediated Intramolecular Pauson-Khand Reaction of Fluorinated and Chiral N-Tethered 1,7-Enynes.

The Co2(CO)8-mediated intramolecular Pauson-Khand reaction is an elegant approach to obtain cyclopentenone derivatives containing asymmetric centers. In this work, we employed density functional theory calculations at the M11/6-311+G(d,p) level of theory to investigate the mechanism and reactivity for the Pauson-Khand reaction of fluorinated and asymmetric N-tethered 1,7-enynes. The rate-determining step was found to be the intramolecular alkene insertion into the carbon-cobalt bond. The stereoselectivity of the alkene insertion step was rationalized by the different transition states showing the coordination of the alkene through the Re- and Si-face. The effects of different fluorine groups and steric effects on both the alkenyl and alkynyl moieties were also theoretically investigated.