Michael Addition Methyl Vinyl Ketone And

2 nitropropane with methyl acrylate.

Michael addition methyl vinyl ketone and.

Propargylamines are synthesized from methyl vinyl ketone derivatives 1 alkynes and secondary amines catalyzed by cu salts involving the michael addition of amine followed by an unusual c c bond cleavage and addition of metal acetylides formed in situ to iminium ions. It was discovered by robert robinson in 1935 as a method to create a six membered ring by forming three new carbon carbon bonds. Michael addition mechanism step 1. The reactions could be carried out without any catalysts and solvents.

In this approach the di tri and tetrasubstituted propargylamines are synthesized in 46 98 yields. Mechanism of the robinson annulation. In this scheme r and r on the. Mesityl oxide with diethyl malonate.

But a kinetically controlled 1 2 addition is also possible which is preferred at low temperatures as shown below. Diethyl malonate with diethyl fumarate. The method uses a ketone and a methyl vinyl ketone to form an α β unsaturated ketone in a cyclohexane ring by a michael addition followed by an aldol condensation. Hydrolysis of ester groups and decarboxylation occurs in the final step.

It combines two reactions. The first step in the process is the michael addition to an α β unsaturated ketone such as methyl vinyl ketone ethyl vinyl ketone is shown above. The carbonyl containing compound is attacked by the base in the first step of the michael addition mechanism. 1 michael addition of diethyl malonate with methyl vinyl ketone followed by protic workup yields a 1 5 dicarbonyl compound.

The reaction donors are active methylenes such as malonates and nitroalkanes and the acceptors are activated olefins such as α β unsaturated carbonyl compounds. Nitropropane with methyl vinyl ketone. Many asymmetric variants exist. The michael addition is thermodynamically controlled.

The michael reaction or michael addition is the nucleophilic addition of a carbanion or another nucleophile to an α β unsaturated carbonyl compound containing an electron withdrawing group it belongs to the larger class of conjugate additions this is one of the most useful methods for the mild formation of c c bonds. The michael addition and the aldol condensation. Michael addition to methyl acrylate and methyl vinyl ketone of n b benzylidene l tryptophan methyl ester 1 gave 2 3 indolylmethyl glutamic dimethyl ester 2a and α 3 oxobutyl tryptophan methyl ester 2b respectively. Silica gel mediated michael addition of 1 3 dicarbonyl compounds to methyl vinyl ketone mvk and ethyl vinyl ketone evk was carried out to give the corresponding adducts in quite excellent yields.

Addition to acrylonitrile of 1 yielded α n a dicyanoethyltryptophan methyl ester 3. The 1 4 addition or conjugate addition of resonance stabilized carbanions.