Efficient Synthesis of Cyclopropylamine Derivatives via Deoxygenative Cyclopropanation of Aliphatic Aldehydes with Stable Sulfur Ylides.

Herein, we report a multicomponent reaction of aliphatic aldehydes, acyl-stabilized sulfur ylides, and hydrazones that provides streamlined access to cyclopropylamine derivatives. The reaction displays excellent stereoselectivity, a broad substrate scope, good functional group tolerance, and needs mild reaction conditions. In addition, the cyclopropylamine products can be smoothly converted into a diverse range of functionalized 1,4-dihydropyridazines through a possible Cs2CO3-promoted ring-opening/intramolecular cyclization/1,2-hydride-shift cascade.