Substrate-controlled [4+1] and [3+2] annulations of ninhydrin-derived Morita–Baylis–Hillman carbonates to access polysubstituted furans and cyclopentenes

The substrate-enabled switching of the regioselectivity allows for efficient regiocontrol via [4+1] and [3+2] annulations of ninhydrin-derived MBH carbonates with α,β-unsaturated ketones to access highly substituted furans and cyclopentene.