Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated carboxylic acids (including β,β-disubstituted acrylic acids) was developed and optimized, which provided a mild and convenient method for the highly challenging synthesis of β-quaternary carbons substituted carboxylic acids.

•Highly reactive cationic Pd(II)-bpy was in situ generated in CH3NO2.•High yielded Pd(II)-catalytic addition to arylaldimines was optimized.•Air and moisture insensitive Pd(II)-catalysis was developed.•12 of 13 examples yielded >90% and showed high functional groups tolerance.An in situ generated cationic Pd(II)/bipyridine-catalyzed nucleophilic addition of arylboronic acids to N-sulfonyl arylaldimines was developed and optimized, and the reaction was proceeded highly efficiently and conveniently in CH3NO2. A series of arylboronic acids and N-sulfonyl arylaldimines were surveyed, and 12 of 13 examples gave 90∼96% yields.Download high-res image (36KB)Download full-size image

•Pd-catalyzed conjugate addition of arylboronic acids to α,β-unsaturated amides.•The reaction was optimized and the substrates scope investigated.•Modest to excellent yields were given for different substrates.•The reaction is oxygen and moisture insensitive.The Pd(II)/bipyridine-catalyzed conjugate addition of arylboronic acid to α,β-unsaturated amides was developed and optimized, and the reaction was proceeded smoothly in air. A series of arylboronic acid and α,β-unsaturated amide substrates were surveyed, and modest to excellent yields were given.

Cobalt-catalyzed cyclization of CO, imine, and epoxide has been developed. A convenient catalyst system composed of Co2(CO)8 and LiCl is identified, and the substrate scope has been explored. The reaction provides an efficient method for the synthesis of substituted 1,3-oxazinan-4-ones.