Green synthesis of tetra-substituted 2H-pyrans catalyzed by lipase in aqueous medium

An efficient and environmental method was employed to synthesize multi-substituted 2H-pyran from methyl coumalate and β-keto esters or diketones. Porcine pancreas lipase (PPL) can catalyze this transformation in high yields (74–96%) in aqueous medium (H2O: DMSO = 2:1) under mild conditions (60 °C). The reported strategy exhibits high functional group compatibility and broad substrate scope. In addition, it provides access to a variety of tetra-substituted 2H-pyrans which are considered privileged scaffolds with diverse biological activities.