N-Boc-Amino Acid Mediated Morita-Baylis Hillman reaction of methylphenyl glyoxylate

Abstract

The organocatalyzed Morita-Baylis Hillman (MBH) reaction of ?-keto esters is a challenging carbon-carbon bond-forming reaction. We developed a catalytic system for the MBH reaction of methylphenyl glyoxylate with methyl vinyl ketone in a polar aprotic solvent. We used N-Boc-L-pipecolinic acid as a proton transfer mediator and 4-dimethylaminopyridine as the tertiary amine catalyst. We obtained the MBH adduct with a 66% yield in 48h. We proposed a detailed reaction mechanism involving a transition state that includes the hydrogen transfer by the acid functional group of N-Boc-L-pipecolinic acid.