Michael addition cyanoacrylate

Michael addition in the absence of any catalytic agent has been reported for dialkyl and diaryl phosphites and thiophosphites with a-cyanoacrylate esters and a-cyanoacrylic acid.444 Yields of the conjugate addition products were moderate to good. The regiochemistry of this process is the opposite of that previously reported for similar additions to ketene acetals, the latter presumably proceeding by initial protonation of the distal olefinic carbon site.445... 

The Michael addition of enaminones 152 and 154 to ethyl 3-cyanoacrylate gives the substituted pyrrolones 153 and 155, respectively. Scheme 40 (84CPB2821). 

A similar cascade reaction was reported by Melchiorre and co-workers [69] in 2008. Initially, this triple cascade reaction between an enolizable aldehyde, 2-cyanoacrylate, and enal consists of the aldehyde addition to a 2-cyanoacrylate derivative (108), promoted by a diphenylprolinol derivative (VII). Next, the resulting adduct reacts with enal via a Michael addition promoted by the same catalyst. Finally, an intramolecular aldol reaction takes place between the formed enamine and the aldehyde, leading to the cyclohexane 109. It should be noticed that the use of an acid as a co-catalyst is cmcial to obtain high levels of stereoselectivity. 

The energetic driving force for conjugate addition is the replacement of a tt bond by a cr bond. Among Michael acceptors that have been demonstrated to react with ketone and ester enolates under kinetic conditions are methyl a-trimethylsilyl-vinyl ketone/ methyl a-methylthioacrylate/ methyl methylthiovinyl sulfoxide, and ethyl a-cyanoacrylate. The latter class of acceptors has been shown to be capable of generating contiguous quaternary carbon centers. 

Extension of this chemistry by alternation of the substrates [41] was conducted soon after. Using a variety of Michael acceptors, in addition to nitroalkenes, cyanoacrylates [42], N-Boc-protected olefinic oxindole [43], or changing a,p-unsaturated aldehyde to... 

The 1,4-addition of [ C]cyanide to appropriate Michael acceptors, such as a, -unsaturated carboxylates 15 and alkyl 3,3-disubstituted 2-cyanoacrylates 12 ... 

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