3-Furanmethanol synthesis

The reaction of several a-diazoketones with ethyl vinyl ether under various conditions has been examined. In the presence of metal salts [Rh2(OAc)4, Pd(OAc)2, CuCl] ethoxy dihydrofurans are produced. The initial product of this reaction sequence is a cyclopropyl ketone which suffers from a spontaneous rearrangement to the dihydrofuran <96CJC2401>. An efficient synthesis of 3-acylfurans is achieved by Ag(I)/Celite mediated cycloaddition of dicarbonyl compounds with vinyl sulfide (<97TL5671> see also <97TL2095>). A two-step synthesis of 2-substituted 4-furanmethanol compounds was reported. The method involves a Homer-Wadsworth-Emmons reaction between 3-ketophosphonates and l,3-diacetoxy-2-... 

Shaw and co-workers used a mixed Lewis acid approach to synthesize chiral furanmethanol derivatives from glycals. These compounds are important intermediates in the synthesis of many biologically significant compounds and serve as precursors for furanmethanes and 3-acylfurans. Reaction of a selectively protected 6-azido glycal with zirconium(IV) chloride and zinc(II) iodide gave the desired chiral furan selectively in 74% yield. 

The alcohol moieties used in the synthesis of the 15 pyrethroids are shown in Table 4. A discussion of the synthesis of each alcohol (i.e., stereochemistry, etc.) is beyond the scope of this review, although allethrone and 5-(phenylmethyl)-3-furanmethanol have been mentioned in the discovery section. Information oti the synthesis of ot-hydroxy-a-(3-phenoxyphenyl) acetonitrile (R, S forms) (cyanohydrin of phenoxyphenyl aldehyde) and the resolution of the desired S form that produces (IR, 3R, a-S) deltamethrin may be found in Chap. 2 of the Deltamethrin Monograph (1982). The alcohols and their metabolites are readily separated by partition chromatography on GC or HPLC columns. Ruzo and Casida (1977) and Ruzo et al. (1978, 1979) used TLC to separate and identify the alcohol metabolites. 

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