Organocadmium reagents addition reactions

A cautionary note must be sounded here, the above explanation being slightly oversimplified. First, electrophilic assistance does not necessarily imply 1,2- addition. Michael reactions occur, even in the absence of cryptands Equally, a rigorously purified organocadmium reagent will not react with enones Li+ or Mg2+ impurities are needed to promote the conjugate addition. 

While most of the chemistry discussed in this chapter has been developed in the past decade, several important methods have withstood the test of time and have made important contributions in areas such as natural product synthesis. Methods such as cuprate acylation and the addition of organolithiums to carboxylic acids have continued to enjoy widespread use in organic synthesis, whereas older methods including the reaction of organocadmium reagents with acid halides, once virtually the only method available for acylation, has not seen extensive utilization recently. In the following discussion, we shall be interested in cases where selective monoacylation of nonstabilized carbanion equivalents has been achieved. Especially of concern here are carbanion equivalents or more properly organometallics which possess no source of resonance stabilization other than the covalent carbon-metal bond. Other sources of carbanions that are intrinsically stabilized, such as enolates, will be covered in Chapter 3.6, Volume 2. 

The Blaise ketone synthesis has been extended to the synthesis of Qf,)0-unsaturated ketones, known as the Blaise-Maire reaction. In addition, the organozinc chloride has been replaced by an organocadmium reagent for a better yield. ... 

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