Michael addition

Also known as: Michael reaction

Schematic of the Michael addition. Reagents: Michael donor - activated methylene (diethyl malonate), Michael acceptor - conjugated olefin (ethyl cinnamate), base catalyst, acid work-up. Product: Michael adduct - addition product. Comments: The reagents could be made of a combination of different EWGs.

The Michael addition is an organic reaction used to convert an activated methylene and a conjugated olefin to the corresponding addition product using a base catalyst followed by an acid work-up. The activated methylene is essentially a methylene bonded to electron withdrawing groups that would stabilize the negative change that forms after deprotonation by the base. This deprotonation results in an enolate which in turn does a 1,4 addition to the conjugated olefin. An acid work-up then provides the final Michael addition product.[1]

Mechanism

Mechanism of the Michael addition. Note: For simplisity we have shown the mechanism using, diethyl malonate, ethyl cinnamate, and sodium ethoxide, the reagents used in the original Michael paper from 1887.

References:

1.
Michael, A. J. Prakt. Chem. 1887, 35, 349–356.