Halomethyl compounds oxidation

Halides are extremely versatile intermediates. One of their more valuable and interesting transformations is their oxidation to carbonyl compounds, thus providing straightforward routes to relatively inaccessible compounds such as 1,2-diketones and heterocyclic aldehydes. As will be seen below, there are many, often complementary, synthetic methods for the oxidation of organic halides. The oxidation of halomethyl compounds has been reviewed recently. ... 

This is one of the oldest methods for the oxidation of halides,and has been used quite widely for the preparation of benzaldehydes and heteroaromatic aldehydes from the halomethyl compounds. Unacti-vat aliphatic halides give reduced yields. 

R = halomethyl, R = benzyloxy ) bound to zinc. Also, compounds containing a diorganoboryl oxide (157) or a triorganosiloxy group (158) form tetrameric aggregates with a hetero-cubane structure. 

Alkylfurans are usually obtained by ring synthesis, decarboxylation of alkylfurancarboxy-lic acids, Wolff-Kishner reduction of aldehydes or ketones, or by reduction of halomethyl groups with zinc and acetic acid or LAH (79JOC3420) alkylation is of limited value. The chemistry of these compounds is conventional but oxidation to furancarboxylic acids cannot usually be carried out due to the lability of the ring. NBS bromination (Section 3.11.2.2.5) is a useful route to side-chain substituted compounds but reduction of esters to hydroxymethyl groups and subsequent transformation is often preferable. The haloalkyl compounds are extremely sensitive to resinification but if adequate precautions are taken they are... 

Thorium oxybromide, 1 54 Tin, as reducing agent for complex tungsten(VI) chlorides in preparation of complex potassium chlorotungstates(III), 6 149 Tin compounds, halomethyl derivatives, by the diazomethane method, 6 37 (CH8) 2 (CH2C1) SnCl, 6 41 Tin (IV) iodide, 4 119 Titanium, powder by reduction of titanium (IV) oxide with calcium, 6 47... 

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