Stoichiometric Reactions of Acylnickel(II) Complexes with Electrophiles and the Catalytic Synthesis of Ketones

Wotal, A., R. Ribson, and D. Weix. Stoichiometric Reactions of Acylnickel(II) Complexes With Electrophiles and the Catalytic Synthesis of Ketones. Organometallics, 5881.
Abstract Acylnickel(II) complexes feature prominently in cross-electrophile coupling (XEC) reactions that form ketones, yet their reactivity has not been systematically investigated. We present here our studies on the reactivity of acylnickel(II) complexes with a series of carbon electrophiles. Bromobenzene, alpha-chloroethylbenzene, bromooctane, and iodooctane were reacted with (dtbbpy)Ni-II(C(O)C5H11)(Br) (1b) and (dtbbpy)Ni-II(C(O)tolyl)(Br) (1c) to form a variety of organic products. While reactions with bromobenzene formed complex mixtures of ketones, reactions with alpha-chloroethylbenzene were highly selective for the cross-ketone product. Reactions with iodooctane and bromooctane also produced the cross-ketone product, but in intermediate yield and selectivity. In most cases the presence or absence of a chemical reductant (zinc) had only a small effect on the selectivity of the reaction. The coupling of 1c with iodooctane (60% yield) was translated into a catalytic reaction, the carbonylative coupling of bromoarenes with primary bromoalkanes (six examples, 60% average yield).
Keywords acid-chloridesaryl-halidesbenzyl halidescarbon-monoxideelectrochemical synthesiselectrosynthesisnickel-carbonylorganic halidesreductive conjugate additionunactivated alkyl-halides
DOI 10.1021/om5004682