Nitrogen transfer reactions with benzyl

Figure 12. Nitrogen transfer reactions with benzyl halides and lithium dialkylaminoborohydrides.

Another example of asymmetric induction in the transfer of chirality from tricoordinate sulfur to the nitrogen atom was reported by Kobayashi (157), who found that methylation of benzylethylani-line with (+)-methoxymethyl-p-tolylsulfonium salt 113 yields (-)-benzylethylmethylphenylammoniumtetrafluoroborate 268. A similar asymmetric methylation reaction was observed with benzyl ethyl sulfide. Chiral ammonium 268 and sulfonium salts 112 were formed... 

Other uses of cobalt(I) catalysts include the reductive intramolecular cyclization of bromocyclohexenones to form bicyclic ketones [391] and the radical cyclization of bro-moacetals [392,393]. Krautler and coworkers [394] found that 1,4-dibromobutane interacts with electrogenerated cob(I)alamin to afford a tetramethylene-l,4-di = Co -cobalamin species. In a recent study of the reactions of cobalt(I) tetraphenyl porphyrin with benzyl chloride or 1-chlorobutane, Zheng and coworkers [395] reported that alkyl radicals are transferred from the cobalt center to a nitrogen of a pyrrole ring, leading to formation of an A-alkyl cobalt porphyrin complex. 

Example 6. The Reaction of l-Benzyl-3-cyanoquinoUnium Ion (BQClSf) with N-Methyl-9,10-dihydroacridine (MAH) in Acetonitrile. The reaction between MAH and BQCN in acetonitrile (Scheme 1.7) has been considered to be an authentic example of a direct hydride transfer reaction mainly due to work of Kreevoy and coworkers. We presented an alternative three-step mechanism in 2003 that was challenged by Perrin and Zhao in 2008." ° The mechanism has been found to be even more complex than we first believed and was shown to involve an oxygen-catalyzed chain reaction even when carried out in a glove-box under a nitrogen atmosphere. ... 

The ozone-mediated reaction of bicumene and some derivatives (11) with nitrogen dioxide in dichloromethane (kyodai nitration) at low temperatures results in the cleavage of the central C—C bond to yield the benzyl nitrate and products therefrom, in contrast to the behaviour of bibenzyl.36 This result is interpreted in terms of electron transfer from the substrate to NO3- to give a radical cation species which fragments to form tertiary benzylic species in the former cases. 

Hamogemeoms catalytic transfer-iyilrogeiiathH. Sa.metal catalyst for transfer of hydrogen from primary alcohols to a,p-unsaturated carbonyl compounds. Thus when benzyl alcohol is heated under nitrogen at 200° for 2 hr. with benzalacetone and the catalyst, benzaldehyde (90% yield) and 4-phenylbutane-2-one (92% yield) are formed. The reaction can be carried out in a... 

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