MAC reagents. Three-components coupling reaction with one carbon homologation

Recent progress of the synthetic study by using Masked Acyl Cyanides (MAC reagents) is described. Various kinds of electrophiles like organohalides, aldehydes, ketons, alpha,beta-unsaturated carbonyl compounds, 1, 3-diene monoxides, allylic carbonates and so on can be transformed to amides or esters with one-carbon homologation. Several syntheses of optically active compounds were demonstrated. Racemization of the alpha-position of the resulting amides and esters was effectively inhibited by the nature of MAC reagents since the resulting carbonyl group is masked as an oxymalononitrile form during the transformation steps. Highly effective one-portion reaction for the connection of three components (aldehydes or ketones, MAC reagent having silyl group, amines or alcohols) was newly developed. A new short-step preparation of MAC reagents is also introduced.