Electrophilic Substitutions at Saturated Carbon Atoms

Abstract

The results obtained in recent years from investigations into the mechanisms of electrophilic substitution reactions at sp3-hybridized carbon atoms are reviewed.

The Dimethylbismuth Cation: Entry Into Dative Bi−Bi Bonding and Unconventional Methyl Exchange

“…corresponds to a bimolecular electrophilic substitution reaction (S E 2 (back)), that is, the electrophilic analog of the wellknown nucleophilic S N 2 substitution reaction in organic chemistry. Methyl exchange along this pathway has rarely been discussed to date, but has been suggested or shown for heterobimetallic systems of late transition metal compounds [28] and for hypothetical systems such as [Li 2 Me] + . [29] To the best of the authors knowledge, the relevance of backside S E 2-type methyl exchange is now for the first time demonstrated for a simple, isolable, (pseudo-)homoleptic, and homometallic compound.…”

Kinetics and mechanism of the cleavage reactions of acylmanganese pentacarbonyl and methylmanganese pentacarbonyl

“…The results have been discussed in several reviews. [8][9][10][11] Many electrophilic centers exist with attached nucleophilic groups. Attack by such a reagent may involve a strong nucleophilic interaction with the metal as well as an electrophilic interaction at carbon.…”

α-Olefin Polymerization with Ether-Coordinated Chromium(III) Alkyls

“…Like 1b , 4b reversibly lost 1 equiv of diethyl ether under vacuum to form green [Cp*Cr(OEt 2 )O i Pr] + BAr‘ 4 - ( 3b ). Cleavage of ethers by strong bases (here the CH 2 SiMe 3 group) is precedented, and the extreme electrophilicity of the cationic, 13-electron chromium center probably enhances the leaving-group tendency of the alkoxide moiety. We attribute the limited thermal stability of 1b to a similar elimination reaction (yielding ethylene and a chromium ethoxide).…”