Kuo JL1, Hartung J, Han A, Norton JR.
J Am Chem Soc. 2015 Jan 28;137(3):1036-9. doi: 10.1021/ja511883b. Epub 2015 Jan 15.Transition-metal hydrides generate α-alkoxy radicals by H• transfer to enol ethers. We have measured the rate constant for transfer from CpCr(CO)3H to n-butyl vinyl ether and have examined the chemistry of radicals generated by such transfers. Radicals from appropriate substrates undergo 5-exo cyclization, with higher diastereoselectivity than the analogous all-carbon radicals. From such radicals it is straightforward to make substituted tetrahydrofurans.