Phase-transfer catalyzed asymmetric arylacetate alkylation

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• 作者：Merritt B. Andrus ; Kaid C. Harper ; Michael A. Christiansen ; Meisha A. Binkley
• 关键词：Phase-transfer catalysis ; Alkylation ; Asymmetric synthesis ; Phenylacetate phenethyl ester ; Cinchona alkaloid catalyst
• 刊名：Tetrahedron Letters
• 出版年：2009
• 出版时间：5 August 2009
• 年：2009
• 卷：50
• 期：31
• 页码：4541-4544
• 全文大小：1327 K

文摘

Phenethyl arylacetates are alkylated under phase-transfer conditions with cinchona catalysts with alkyl halides in high yield with excellent enantioselectivity (84–99 % ee) following recrystallization. Cinchonidine (CD) derived catalyst gave the (R)-product and cinchonine (CN) catalyst produced the (S)-product. The phenethyl (PE) ester group is removed, using ammonium formate and catalytic Pd/C, to give alkylated carboxylic acid products in high selectivity. The utility of the approach is demonstrated by a direct synthesis of (S)-naproxen<sup>™sup>.