Organocatalytic Enantioselective Vinylcyclopropane‐Cyclopentene (VCP‐CP) Rearrangement

We have demonstrated that the catalytic and enantioselective vinylcyclopropane-cyclopentene rearrangement can be carried out on (vinylcyclopropyl)acetaldehydes through activation via enamine intermediates. The reaction makes use of racemic starting materials that, upon ring opening facilitated by the catalytic generation of a donor-acceptor cyclopropane, deliver an acyclic iminium ion/dienolate intermediate in which all stereochemical information has been deleted. The final cyclization step forms the rearrangement product, showing that chirality transfer from the catalyst to the final compound is highly effective and leads to the stereocontrolled formation of a variety of structurally different cyclopentenes. Grants PID2019-104090RB-100 and PID2020-118422GB-I00 funded by MCIN/AEI/10.13039/501100011033 and by “ESF Investing in your future” are gratefully acknowledged together with the Basque Government (Grupos IT1558-22) and the Government of Aragón (Grupos Consolidados, E34-20R and a fellowship to M. P.). G. G. also thanks the Spanish Ministerio de Universidades for an FPU grant. The authors thankfully acknowledge the resources from the supercomputers “Memento” and “Cierzo”, technical expertise and assistance provided by BIFI-ZCAM (Universidad de Zaragoza, Spain).