C_sp³–C_sp³ and C_sp³–H Bond Activation of 1,1-Disubstituted Cyclopentane

The unprecedented Csp3–Csp3 bond cleavage of unactivated cyclopentane has been achieved. RhI-catalyzed cycloaddition of allenylcyclopentane-alkynes produced in situ the 9-cyclopentyl-8-rhodabicyclo[4.3.0]­nona-1,6-diene intermediates, which subsequently underwent [7+2] cycloaddition via β-C elimination, affording bicyclo[7.4.0]­tridecatriene derivatives in good yields. Changing the RhI catalyst effected the Cγ–H bond activation of the common 9-cyclopentyl-8-rhoda­bicyclo[4.3.0]­nona-1,6-diene intermediate to produce the novel spiro[2.4]­heptane skeleton in a site-selective manner.