Carbometallation of alkenes

This chapter is intended to highlight recent results in the fields of intra- and intermolecular carbometallation, but we will concentrate only on the chemistry of lithium and zinc derivatives. Although the Group IV metallocene-mediated reductive cyclizations of enynes [36] and dienes [36], and the use of transition metals of Group VIII, as well as the more recent development of the organolanthanide chemistry [37] followed by selective reaction with different electrophiles [36], represent an important methodology for the construction of polysubstituted carbocycles, they will not be addressed here. 

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Scheme 6 Unified scheme for carbometallation of alkenes with transition metal complexes.

Syntheses of isolable organometallic species by carbometallations of alkenes are difficult because many side reactions can occur, namely p-hydride elimination and chain propagation. As a consequence, only a few examples have been reported to date, mainly concerning reactions in which the initial carboalumination product is trapped through fast intra-... 

Carbometallation of alkenes and alkynes is attracting considerable interest as a potential new method for C—C bond formation. A general treatment is available by Negishi a leading expert of the field.632... 

Pyrrolidines and pyrrolidinones can be synthesized on insoluble supports by intramolecular carbometallation of alkenes (Entry 1, Table 15.4) and by Ugi reaction of support-bound isonitriles with amines and 4-oxo acids (Entry 4, Table 15.4). In Entry 5 in Table 15.4, the pyrrolidinone ring is formed by intramolecular Diels-Alder reaction of a furan with a fumaric acid derivative. 2-Pyrrolidinones have also been prepared by treatment of resin-bound O-mesitylenesulfonyl cyclobutanone oximes with... 

Catalytic enantioselective single-stage carbometallation of alkenes had until recently been an elusive synthetic goal, even though its principle and potential feasibility were recognized. It is... 

The insertion of alkene to metal hydride (hydrometallation of alkene) affords the alkylmetal complex 34, and insertion of alkyne to an M—R (R = alkyl) bond forms the vinyl metal complex 35. The reaction can be understood as the cis carbometallation of alkenes and alkynes. 

Cross-coupling with alkenes (carbometallation of alkenes)... 

Cross-coupling with Alkenes (Carbometallation of Alkenes)... 

The addition of an organometallic to an unactivated olefin is generally difficult to control since such an addition may lead to polymerization of the olefin unless the final organometallic adduct is stabilized, or has a structural modification. Thus, no general reaction for the intermolecular carbometallation of alkenes is known, although since the last review concerning this topic [3], many relevant papers have appeared. 

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