Addition reaction 3-methyl-3-hydroxy-2-butanone

Out first example is 2-hydroxy-2-methyl-3-octanone. 3-Octanone can be purchased, but it would be difficult to differentiate the two activated methylene groups in alkylation and oxidation reactions. Usual syntheses of acyloins are based upon addition of terminal alkynes to ketones (disconnection 1 see p. 52). For syntheses of unsymmetrical 1,2-difunctional compounds it is often advisable to look also for reactive starting materials, which do already contain the right substitution pattern. In the present case it turns out that 3-hydroxy-3-methyl-2-butanone is an inexpensive commercial product. This molecule dictates disconnection 3. Another practical synthesis starts with acetone cyanohydrin and pentylmagnesium bromide (disconnection 2). Many 1,2-difunctional compounds are accessible via oxidation of C—C multiple bonds. In this case the target molecule may be obtained by simple permanganate oxidation of 2-methyl-2-octene, which may be synthesized by Wittig reaction (disconnection 1). 

Percent product distribution 2-methyl-propanal 48.1 1.1, 2-hydroxy-3-methyl-butanal 6.9 0.34, l-hydroxy-3-methyl-2-butanone 29.5 0.61, 1,2-dihydroxy-3-methy 1-butane 15.5 1.1. Data evaluation in a manner similar to that for 1-butene showed 24 % of OH addition to occur at the inner and 76 % at the outer position of the double bond, = 0.82 0.02, and 38% reaction of... 

Methyl ketones from esters (12, 126).1 The reaction of a carboxylic acid or ester with CH3Li and ClSi(CH3)3 to provide a methyl ketone has been used to obtain a silyl protected (S)-3-hydroxy-2-butanone (2) from ethyl lactate (1). The addition of... 

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