Asymmetric Synthesis and Catalytic Activity of 3-Methyl-尾-proline in Enantioselective anti-Mannich-type Reactions

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• 作者：Kazuhiro Nagata ; Yasushi Kuga ; Akinori Higashi ; Atsushi Kinoshita ; Takuya Kanemitsu ; Michiko Miyazaki ; Takashi Itoh
• 刊名：The Journal of Organic Chemistry
• 出版年：2013
• 出版时间：July 19, 2013
• 年：2013
• 卷：78
• 期：14
• 页码：7131-7136
• 全文大小：295K
• 年卷期：v.78,no.14(July 19, 2013)
• ISSN：1520-6904

文摘

Enantiomerically pure 3-methyl-尾-proline was synthesized using an asymmetric phase-transfer-catalyzed alkylation of a cyanopropanoate to establish the all-carbon stereogenic center. The catalytic activity of 3-methyl-尾-proline in the Mannich-type reaction between a glyoxylate imine and ketones/aldehydes was subsequently investigated. The catalyst was designed and found to be more soluble in nonpolar organic solvents relative to the unsubstituted 尾-proline catalyst, and as a result allowed for added flexibility during optimization efforts. This work culminated in the development of a highly anti-diastereo- and enantioselective process employing low catalyst loading.