In recent years, many reports have been published dealing with new syntheses of many types of organic compounds from organoboranes. 192 However, there is no successful report on the direct preparation of carboxylic acids via organoboranes, although various attempts have been made utilizing the reactions of organoboranes, for example, with cyanide ion followed by protonolysis,3 and with 1,1-dichloromethyl methyl ether in the presence of bases. 6 In the course Bo. 32 PhOq R3B + PhOCHCOO -)CHCOO __+ RzB, R;B,f R ,CHCOO +H+_ RCH2COOH (3) R The reaction is exceedingly simple. The dianion of phenoxyacetic acid can be readily prepared by treatment of 2 equivalents of lithium diisopropylamide in tetrahydrofuran at 0". This dianion is unusually soluble in tetrahydrofuran and can be prepared without any polar solvent such as HMPA' or any heating of the system. 10 Tributylborane reacts with the anion at 66' in 2 h followed by the usual alkaline hydrogen peroxide oxidation and acidification with hydrochloric acid to give hexanoic acid in an essentially quantitative yield.