2-Methylene-prim-alcohols

NaBr02 3H20 and 4-r rr-butylcyclohexanol with a small amount of methylene chloride added sequentially to AI2O3 in the same solvent, and stirred for 24 h at room temp. - 4-r rr-butylcyclohexanone. Y 98%. Aliphatic prim, alcohols gave esters in poor yield. F.e., also aryloxo compds. from benzyl alcohols, s. T. Morimoto et al., J. Chem. Soc. Perkin Trans. I 1988, 2423-4. 

Prim, alcohols from methylene compounds—Organoaluminum compounds s. 11, 713 s.a. A. 629, 241 (1960)... 

A soln. of benzyl alcohol in methylene chloride added to a mixture of trifluoromethanesulfonic anhydride and 2 eqs. acetonitrile in the same solvent at room temp., and after 5 h hydrolysed with satd. NaHCOq soln. - N-benzylacetamide. Y 87%. The method is complementary to the standard procedure in coned. H2SO4 which is only applicable to tert. alcohols here, yields are optimum with prim, and sec. alcohols, whereas tert. alcohols undergo competitive elimination. F.e.s. A.G. Martinez et al.. Tetrahedron Letters 30, 581-2 (1989). 

A soln. of cholesterol, tetra-O-benzyl-a-D-glucosyl chloride, and tetramethylurea in methylene chloride refluxed for 2 h through a column containing 4A molecular sieves, solvent removed, and the residue heated to 120° for 4 h product. Y 92% (a P 60 40). When the reaction was carried out at 120° for 2 h without preliminary removal of water, the yield was reduced (79%) but the a-selectivity increased to 85 15. The method is simple (applicable to both prim, and sec. alcohols) and does not require a hazardous metal. F.e. and reaction in the absence of TMU s. M. Nishizawa et al., Chem. Pharm. Bull. 37, 565-7 (1989) from 2 -unprotected glycosyl chlorides s. Tetrahedron Letters 29, 4597-8 (1988). 

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