Use of water as a direct hydrogen donor in supercritical carbon dioxide: a novel and efficient Zn–H2O–CO2 system for selective reduction of aldehydes to alcohols

This is the first report that Zn–H2O–CO2 is an excellent reducing reagent for the reduction of aldehydes in supercritical carbon dioxide (scCO2). The corresponding alcohols were obtained in good yields and excellent selectivity. The experimental results showed that scCO2 plays an important role in this reduction.