An Efficient Partial Reduction of α,β-Unsaturated Esters Using DIBAL-H in Flow.

The partial reduction of α,β-unsaturated esters and benzoate derivatives to form the corresponding aldehydes was achieved using a flow reactor system within 1 s at a high flow rate (18 mL min-1) under cryogenic conditions (-97 °C). Commercially available diisobutylaluminium hydride (DIBAL-H) was used as the reductant. The desired enals and benzaldehyde derivatives, except for 4-methoxycinnamate and 4-methoxybenzoate, were formed selectively and redox economically in moderate to high yields. [ABSTRACT FROM AUTHOR]