Benzyl methyl carbonate reactions with

The reaction of benzyl methyl carbonate with sodium benzenesulflnate and different palladium catalysts has shown that the best yields were obtained when a Pd( 3-C3H5)Cl2 - (DPEphos) catalyst was used in DMSO at 80 °C.121 Most of the reactions gave >90% yields of the benzyl aryl sulfone. In the suggested mechanism, the methyl carbonate leaving group is displaced by the catalyst, forming an (j 3-benzyl)palladium intermediate that reacts with the sodium salt of the arenesulfinate. 

Substitution reactions. Benzylation of phenols by benzyl methyl carbonates with Pd catalysis proceeds via transesterification and decarbonylation. Triarylmethanes are obtained from a reaction of benzhydryl carbonates with arylboronic acids. ... 

The reaction of benzyl radicals wdth several heterocyclic compounds W as more extensively studied by Waters and Watson, " - who generated benzyl radicals by decomposing di-tert-butyl peroxide in boiling toluene. The products of the reaction with acridine, 5-phenyl-acridine, 1 2- and 3 4-benzacridine, and phenazine were studied. Acridine gives a mixture of 9-benzylacridine (17%) (28) and 5,10-dibenzylacridan (18%) (29) but ho biacridan, w hereas anthracene gives a mixture of 9,10-dibenzyl-9,10-dihydroanthracene and 9,9 -dibenzyl-9,9, 10,10 -tetrahydrobianthryl. This indicates that initial addition must occur at the meso-carbon and not at the nitrogen atom. (Similar conclusions were reached on the basis of methylations discussed in Section III,C.) That this is the position of attack is further supported by the fact that the reaction of benzyl radicals with 5-... 

One interesting observation deduced from the data of Table 13 is that, despite the same diastereomeric ratio, the absolute configuration around the carbon atom of the major diastereomer changed with the electrophile used. In other words, the reactions of a-lithiobenzyl sulfoxides with 020 - and its carbonylation and carbonation proceeded with retention of configuration, while methylation with CHjl resulted in inversion . The stereochemical study of these reactions was conducted with optically active benzyl sulfoxides 42 and 39 as shown in Scheme i - - nd an interesting... 

The authors concluded that the transition states for the Menshutkin reactions of the benzyl substrates were early (reactant-like) with nitrogen-alpha carbon bond formation lagging behind alpha carbon-oxygen bond rupture. The transition states for the Menshutkin reactions with the methyl and ethyl substrates, on the other hand, are tight (product-like) with nitrogen-alpha carbon bond formation greater than alpha carbon-oxygen bond rupture. 

If a carbon atom bearing a positive charge is bound with the methyl group, the reaction path consists of a methyl proton loss. This is the intrinsic property of methyl derivatives in the cation-radical state. The deprotonation generates a benzylic-type radical that is rapidly oxidized to a so-called benzylic carbocation, which reacts with a nucleophile as shown in Scheme 3.70. From Scheme 3.70 it is clear that BP-6-methyl can act as an active carcinogen (Cavalieri and Rogan 1995). 

In marked contrast to this behaviour, monomer 11, l-benzyl-2-methyl-aziridine, gives a relatively slow reaction with Et30+BF4. However, polymerisation is quantitative and all the indications are that the system is living . Why this would be so is difficult to explain. Electronic factors would seem to be elimi-minated since this monomer is intermediate as far as basicity is concerned. Presumably the explanation lies in the stereochemistry of the system since this particular monomer is the only carbon substituted species. Even more strangely, however, the closely related molecule l-benzyl-2-ethyl-aziridine is reported (141) to behave like 8,9, and 10 when treated with boron trifluoride. 

Reactions with Acyl Halides. The palladium-carbon bond in alkyl VII and acyl VIII complexes also can be broken by acyl and alkyl halides, respectively, to give ketones (55). The reaction of the benzyl complex Vila with acetyl chloride in the presence of 2,6-lutidine provided good yield of methyl benzyl ketone, XVII. In the absence of the base, lower yields (26% ) were obtained. Surprisingly, a similar reaction between the benzyl complex and an excess of phenylacetyl chloride afforded a 156% yield of dibenzyl ketone, XVIII, based on the starting benzyl complex (see bottom of p. 105). 

Triorganyl-sulfonium, -selenonium and -telluronium salts are reduced by carbon dioxide radical anions/solvated electrons produced in aqueous solution by radiolysis. The radical expulsion accompanying reduction occurred with the expected leaving group propensities, i.e. benzyl > secondary alkyl > primary alkyl > methyl > phenyl. Much higher product yields in the reduction of selenonium and telluronium compounds have been accounted for in terms of a chain reaction with carbon-centred radicals, with formate serving as the chain transfer agent.282... 

Benzyl acetates react with trimethylsilane and CO in the presence of Co2(CO)8 as catalyst to give P-phenethyl alcohols by a one-carbon homologation. The active catalyst is assumed to be (CH3)3SiCo(CO)4. The reaction proceeds under CO at atmospheric pressure at 25°. It fails with benzyl alcohol itself, but is successful with benzyl formate and benzyl methyl ether.5... 

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