Tandem, Catalyst-Free C-C Synthesis of Nitriles from Aldehydes and Methyl Cyanoacetate with Sodium Hypophosphite

Saturated carbon chain elongation is a common refrain in numerous synthetic pathways. While the formation of C-C single bonds is of primary importance in organic synthesis, simultaneous introduction of functional groups such as nitrile or ester can reasonably increase its practical utility to prepare multifunctional products. Knoevenagel reaction is one of the powerful tools to create carbon backbones of organic molecules; however, it requires subsequent reduction and/or decarboxylation to achieve a product with a saturated carbon chain. Herein we report a convenient one-step protocol for the reductive condensation between methyl cyanoacetate and aldehydes in the presence of stable, ecologically benign, cheap and available in bulk amounts sodium hypophosphite as a reductant. A description of both the reaction capabilities and limitations is given in this paper.