Bifunctional 2,5-Diketopiperazines as Efficient Organocatalysts for the Enantioselective Conjugate Addition of Aldehydes to Nitroolefins
作者:Marco Durini、Florian A. Sahr、Michael Kuhn、Monica Civera、Cesare Gennari、Umberto Piarulli
DOI:10.1002/ejoc.201100794
日期:2011.10
synthesized. DKP-1 and DKP-2 are bifunctional diketopiperazines formally derived from the head-to-tail cyclization of L-aspartic acid and either (R)- or (S)-2,3-diaminopropionic acid, which feature aminomethyl and carboxymethyl side arms in the 3- and 6-positions of the 2,5-piperazindione ring. Peptidomimics (3–6) were tested as organocatalysts in the conjugate addition of several aldehydes to β-nitrostyrene
合成了四种含有顺式 DKP-1 或反式 DKP-2 支架和 L-Pro 或 D-Pro 的肽模拟物 (3-6)。DKP-1 和 DKP-2 是双功能二酮哌嗪,形式上源自 L-天冬氨酸和 (R)- 或 (S)-2,3- 二氨基丙酸的头对尾环化,具有氨甲基和羧甲基侧臂在 2,5-哌嗪二酮环的 3 位和 6 位。肽模拟物 (3-6) 作为有机催化剂在几种醛与 β-硝基苯乙烯和 (E)-2-(呋喃-2-基) 硝基乙烯的共轭加成中进行了测试,具有良好到出色的非对映选择性和对映选择性。使用丙醛对四种催化剂及其烯胺衍生物进行蒙特卡罗/能量最小化 (MC/EM) 构象搜索,以使观察到的立体选择性合理化。