A-Alkoxylactones

A soln. of 0.5 mole of ethyl a-hydroxyisobutyrate in ether added dropwise to a soln. of p-dimethylaminophenyllithium prepared from 2 moles of p-bromo-dimethylaniline and 4 moles of small pieces of Li-ribbon (preferably containing ca. 0.6% Na) in anhydrous ether under Ng, and refluxed 5 hrs. l,l is-(p-di-methylaminophenyl)-2-methyl-1,2-propanediol. Y 86% based on ethyl a-hydroxyisobutyrate. F. e., also with a-alkoxyesters and a-alkoxylactones, s. J. B. Wright and E. S. Outsell, Am. Soc. 81, 5193 (1959) optically active compounds s. D. J. Gram et al.. Am. Soc. 81, 5740 (1959) effect of sodium content of lithium on the prepn. of organolithium compounds s. a. G. W. Kamienski and D.L. Esmay, J. Org. Ghem. 25, 1807 (1960). 

The direct bromination of -alkoxylactones at the p position initially generates the a. -unsaturated lactones (eq 14) however, the required radical abstraction is not so facile and further bronii-nation of the Q , -unsaturated lactone proceeds competitively to afford the mono- and dibrominated products. NBS is also used for the oxidative aromatization of polycyclic compounds, including steroids and anthraquinone precursors (eq 15). ... 

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