Magnesium organo-complexing

Scheme 1 Reactions of the magnesium complex of 1,2-dimethylenecyclohexane with organo-dibromides.

Introduction The structure of organo-lithium compounds Lithium and Magnesium Complexes... 

These methods of acylation are devices to solve the problem that acid chlorides and organo-lithium or magnesium derivatives are not good partners. To get good acylation with acid chlorides, as well as good alkylation with alkyl halides, we need to turn to other metals which provide softer carbanion complexes, less basic compounds with metals showing a lower affinity for oxygen. The most important is copper. 

Reaction of nonstabilized carbanions with [Fp(olefin)] complexes generally results in either displacement of the olefin or reduction of the metal rather than formation of stable (j -alkyliron complexes. This is especially true with simple, nonstabilized organo-magnesium halide or lithio reagents. However, allylmagnesium chloride and phenylmag-nesium chloride react in modest (20-40%) yield with the ethylene, propene and butadiene (1,4 addition) iron complexes. Lithium dimethylcuprate is even more efficient, reacting in up to 70% yield with Fp complexes of styrene, butadiene (1,4 addition) isoprene (1,4 addition) and allene. Complexes of cyclopentene and allene react in low... 

Of the wide range of organo-metallic complexes likely to exist in natural waters only a small number have been structurally identified. Two examples of identified complexes found in sea water are cobalt(II)-containing cyanocobalamine or vitamin B,2 (Carlucci, 1970) and magnesium in chlorophyll a (Riley and Chester, 1971). Although a great deal is known about the properties of the unidentified complexes, it is not possible to classify them according to the systematic molecular nomenclature used in classical chemistry (lUPAC, 1973 Cahn, 1974). This undoubtedly has contributed... 

---