Organomanganese/amido-phosphine (DAPTA) catalyst for rapid cyanosilylation of aldehydes in glycerol and solvent-free conditions at room temperature

A mixture of the organomanganese precursor [CpMe-Mn(CO)3] and the amido-phosphine 3,7-diacetyl-1,3,7-tri-aza-5-phosphabicyclo[3.3.1]nonane (DAPTA) has been utilized in a highly efficient homogeneous catalytic process for the cyanosilylation of aromatic and aliphatic aldehydes in glycerol and under solvent-free conditions. A catalyst loading as low as 0.1 mol % led to a quantitative conversion of various aldehydes into the corre-sponding cyanohydrins in 15 min at room temperature. Multinuclear NMR and ESI(+)MS analysis revealed a mechanism conceivably evolving via a double activation process where DAPTA acts as a Lewis base and the in situ generated [CpMe-Mn(DAPTA)(CO)2] organomanganese species as a Lewis acid.

Automated summary

A highly efficient homogeneous catalytic process for the cyanosilylation of aromatic and aliphatic aldehydes in glycerol and under solvent-free conditions has been achieved using a mixture of the organomanganese precursor [CpMe-Mn(CO)3] and the amido-phosphine 3,7-diacetyl-1,3,7-tri-aza-5-phosphabicyclo[3.3.1]nonane (DAPTA). A catalyst loading as low as 0.1 mol % resulted in quantitative conversion of various aldehydes into the corresponding cyanohydrins in 15 min at room temperature. Mechanistic studies suggest a double activation process involving DAPTA as a Lewis base and the in situ generated [CpMe-Mn(DAPTA)(CO)2] organomanganese species as a Lewis acid.