Synthesis of α-silylcarboxylic acids

Synthesis of α-germyl and α-silylcarboxylic acids and selected electrochemical oxidations

“…Me 3 GeCH 2 COOH [2À(trimethylgermyl)acetic acid, (I)] was prepared according to the procedure previously described for the synthesis of a-silylcarboxylic acids [6,7]. In a typical example for the synthesis of 2À(trimethylgermyl)acetic acid (I), diisopropylamine (10.7 mmol, 1.63 ml) and anhydrous tetrahydrofuran (30 ml) were added to an oven dried round-bottomed flask (100 ml) equipped with a magnetic stirring bar.…”

“…The residual product was crystallized from hexane to give 1.80 gr (80%) of pure 2À(trimethylgermyl)acetic acid (I). 1 a-Germyl, a-silylcarboxylic acid IV was prepared by quenching the dianion of Ph 2 (Me)SiCH 2 COOH with Me 3 GeCl, similar to the alkylation of I to generate II, according to a known procedure [7].…”

“…This synthesis has been reported before [7]. The following quantities have been used: a-Diphenyl(methyl)silyl-4-pentenoic acid (XI): diphenyl(methyl)silylacetic acid (6.98 mmol, 1.79 g) was reacted with LDA (15.4 mmol) and allylbromide (7.68 mmol, 0.66 ml).…”

“…Acid I could be further transformed into other carboxylic acids (II and III) by direct alkylation of its dianion, similar to the procedure for the silyl analog [7] (Scheme 3).…”

“…An efficient synthesis of a-silylacetic acids with various substituents attached to the silicon atom (R 0 R 00 R 000 SiCH 2 COOH), as well as of a-silylcarboxylic acids with various alkyl groups at the aposition [R 0 R 00 R 000 SiCH(R)COOH] has been described previously [6,7].…”