Esters from Grignard reagents

Preparation of Tertiary Alcohols from Esters and Grignard Reagents... 

PREPARATION OF TERTIARY ALCOHOLS FROM ESTERS AND GRIGNARD REAGENTS... 

The formation of halogenation products from Grignard reagents and sulfonic acid anhydrides is the result of an oxidative reaction pathway . This side-reaction can be reduced by using sulfonic acid esters, however, in these cases alkylations as well as twofold sulfonylations (cf. corresponding results with sulfonyl fluorides ) are competing (equations 64 and 65). 

Table 11.5. Substituted cyclopropanols 31 from carboxylic acid esters and alkenes via ligand-exchanged titanium intermediates generated from Grignard reagents and XTi(OiPr)3 (X = OiPr, Cl, Me).

The procedure described4 is a modification of the method of Khotinsky and Melamed,8 who first reported the preparation of boronic acids from Grignard reagents and borate esters. Benzeneboronic acid and the corresponding anhydride also have been prepared by reaction of phenylmugnesium bromide with boron... 

Symmetrical alcohols can in fact be made in one step from Grignard reagents and esters, as the reaction first produces the aldehyde 57 which is more electrophilic than the ester and so reacts again. There is a warning here Aldehydes cannot be made by acylation of Grignard reagents with esters. But if two reactions are wanted, this is a good method. 

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