Benzyl alkoxide

More recently, we have developed aromatic heterocyclic pyrazol-5-one-based tridentate N,N,0-donor ketiminate-supported magnesium and zinc benzyl-alkoxide systems [L2M2(p-OBn)2] where M = Mg 45 or Zn 46, and L = 4-... 

Fig. 17.50. One-pot synthesis of an alkyl-substituted aromatic compound that involves a dissolving lithium reduction of a benzyl alkoxide.

Figure 17.50 shows how a benzyl alkoxide can be reduced in this way. Here, the reduction is part of the synthesis of an alkylated aromatic system. The target molecule contains a primary alkyl group. It is not possible to introduce this alkyl group by way of a Friedel-Crafts alkylation into the ortho-position of anisole in a regioselective fashion and without rearrangements (see Section 5.2.5). 

Benzyl alkoxide, generated from benzyl alcohol and potassium hydride, reacted with 1,1-bis-(benzenesulfonyl)cyclopropane (5a) to give 3-benzyloxy-l,l-bis(benzenesulfonyl)propane (6a) after quenching the reaction with water. The reactivity of benzenesulfonyl-substituted cyclopropanes towards nucleophiles was demonstrated by the reaction of methyl 2,2-dimethyl-l-benzenesulfonylcyclopropanecarboxylate (6b) with methanol which added across the most substituted cyclopropyl bond. ... 

The formation of K)-ester carbonyl label was explained by assuming that some transesterification took place (Crowley et al., 1973) even when using the hindered triethylcarbinyl ester, resulting in scrambling of HT label (Scheme 9-4). Two paths for scrambling of C label, shown in Scheme 9-4, involve the participation of polymeric benzyl alkoxide ion (Path A) and triethylcarbinyl alkoxide ion, followed by retransesterification by polymer alkoxide (Path B), respectively. From the C-label distribution, it was concluded that Path A was the major route for transesterification. Furthermore, it was shown that, if the triethylcarbinyl ester... 

Encouraged by these results, the reaction of benzylic alkoxides with dichloroborane was examined. These reactions provide an alternative route to diarylmethane derivatives (Schane 23.77). The deoxygenation of alkoxides using dichloroborane provides useful evidence for understanding the importance of Lewis acidity in previously reported deoxygenation methods operating through alkoxide intermediates. ... 

SCHEME 23.77 Reaction of benzylic alkoxides with dichloroborane. 

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