Synthesis, asym carboxylic acids

Asym. synthesis of carboxylic acids via C-alkylation of N-acylpyrrolidines... 

Startg. oxazoline treated at -78° with Li-diisopropylamide in tetrahydrofuran then with -propyl iodide product. Y 92-95%. - By hydrolysis of the products, chiral acids can be obtained in optical yields of 73-84%, representing an asym. synthesis of carboxylic acids. F. e. s. A. I. Meyers, G. Knaus, and K. Kamata, Am. Soc. 96, 268 (1974) Chem. Commun. 1974y 768 of a-alkoxy- and a-halogeno-carboxylic acids s. Tetrah. Let. 1974, 3495 syntheses with Zl -oxazolines s. a. ibid. 1974, 1333-1341. 

Dilithium tetrachlorocuprate is recommended as an additive for cross coupling of Grignard compounds with tosylates even allylic and benzylic acetates give good yields . a-Methylene-ketones, -carboxylic acids and -lactones have been prepared via sulfides and sulfoxides. A convenient and general synthesis of acetylene derivatives from boranes via the reaction of iodine with lithium 1-alkynyltriorganoborates has been published ar-Nitrostyrenes can be easily obtained by a Wittig synthesis with formaldehyde in an aqueous medium . A new synthesis of unsym. ketones by reaction of dialkyldiloroboranes with lithium aldimines has recently been published . Metallo aldimines have also served for the synthesis of a variety of other compound classes such as a-hydroxyketones, a-keto acids, nitriles, and for the asym. synthesis of a-amino acids . Polycondensations of malononitriles with benzylic chlorides have been carried out quantitatively under mild conditions in dimethyl sulfoxide with triethylamine as acid acceptor . Carbonyl compounds can react with dibromoacetonitrile to yield a-bromo esters with additional carbon atom . ... 

Asym. diene synthesis Reversal of stereospecificity Alcohols from carboxylic acid esters... 

Asym. synthesis of 3-subst. carboxylic acids from chiral 2-yinyl-z1 -oxazolines... 

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