First one-pot organocatalytic synthesis of α-methylene-γ-lactones

All in one pot: an organocatalytic highly enantioselective synthesis of alpha-methylene-gamma-lactones has been reported. The reaction between protected 2-hydroxymalonates and MBH carbonates is simply catalysed by chiral Lewis bases affording after acid treatment the corresponding lactones in excellent yields and enantioselectivities.