Visible-Light-Induced Photocatalytic C–H Alkylation of Diazo Compounds with Morita–Baylis–Hillman Adducts

Under photocatalytic conditions, diazo compounds undergo proton-coupled electron transfer (PCET) activation, generating highly electrophilic alkyl radicals in situ. These reactive intermediates exhibit marked selectivity toward addition of electron-rich olefins, as consistently demonstrated in previous studies. Notably, in this developed protocol, these radicals undergo addition to the electron-deficient olefin moiety of Morita-Baylis-Hillman (MBH) acetates, followed by acetoxy elimination to afford multifunctionalized olefins. This method demonstrates excellent substrate compatibility, accommodating a wide range of structurally diverse diazoacetate derivatives, and enables efficient transformation of MBH acetates under mild condition.