An Efficient Synthesis Of α-Acetoxyl-α,β-Unsaturated Amides Via The Baeyer–Villiger Reaction And Its Application To 5-hydroxy-5-methyl-1H-pyrrol-2(5h)-ones

Since 1899 when Adolf von Baeyer and Victor Villiger first reported the oxidation rearrangement reaction of ketone or cyclic ketone to esters or lactons, with sulfuric acid as the oxidant, after more than a century of development and improvement, Baeyer-Villiger (B-V) reaction has possessed an important seat in the field of organic chemistry synthesis as a very important synthesis of esters. At present, there have been many articles of summary about the B-V reaction. The scope of substrate has been largely expanded and the condition s are improved constantly. Besides, B-V reaction also has been applied in the synthesis of antibiotics and steroids in biochemistry, pheromone in agricultural chemistry,polymerase monomer.The reactions which have reported were main ly focusing on aliphatic ketones andα,β-unsaturated ketones,but the B-V reacti on aboutα,β-unsaturated ketones bearing electron-withdrawing groups at the a site still has seldomly been reported.In recent years, our group, having stared from acetoacetarylamides, which aresimple and commercially available, introduce some substituents like cyclopro pyl, cyanoethyl and alkynyl etc. to develop and build the synthesis of various heterocyclic compounds which have important biological activities, including the synthesis of alkaloids derivatives like furoquinoline, the synthesis of imino lac tone, dihydro-quinolinone, lactam derivatives, constructing the molecular scaffold of natural product Martinelline etc.. through making use of domino reactions with the participation of lewis acid,br(?)nsted acid and transition metal presence. In this paper, we also put our interst on the acetoacetarylamides, utilizing the methylene of acetoacetarylamides'Knoevenagel condensation reaction with al dehydes to afford a-carbonyl-α,β-unsaturated amide, furthermore,we studied the B-V oxidation rearrangement reaction of this peculiarα,β-unsaturated amide s bearing electron-withdrawing groups to corresponding esters with peroxide as oxidants so as to synthesize series of a-acetoxyl-α,β-unsaturated amides and ex pand the substrates'range of B-V reaction. In addition,those oxidation prodctio ns as a kind ofα,β-unsaturated amides bearing electron-donating groups at a position,having high reactivity because of the existence of the acetoxyl and th e carbon-carbon double bonds. For example, cycloaddition reaction can occur when it reacts with another molecule conjugated olefins or 1,3-dipole to construct many organic heterocyclic compounds that have more complex structu re. Thus, further application ofα-acetoxyl-α,β-unsaturated amides'in the field of organic synthesis is very important.This paper designed and achieved the conversion of a-acetoxyl-α,β-unsatur ated amides to y-lactam at alkaline conditions successfully,and discussed the re action mechanism briefly.