Momiyama Norie, Yamamoto Yuhei, Yamamoto Hisashi
Department of Chemistry, University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA.
J Am Chem Soc. 2007 Feb 7;129(5):1190-5. doi: 10.1021/ja066037m.
This article presents complete diastereo- and highly enantioselective synthesis of nitroso Diels-Alder-type bicycloketones using dienamine. With the hydrogen bonding of two hydroxyls in the bulky binaphthol 1c, high enantioselectivities and complete diastereoselectivity are realized in 2-oxa-3-aza-bicycloketone synthesis. On the other hand, alpha,beta-unsaturated ketone can be employed as diene precursor, utilizing readily available tetrazole catalyst 3b, to provide the 3-oxa-2-aza-bicycloketones in moderate yields with complete enantioselectivities. Investigation into the reaction utilizing 2-morpholino-4,4-diphenylcyclohexadiene 2d clearly indicated that cyclization with the bulky binaphthol 1c is involved in the sequential process, the N-nitroso aldol reaction, followed by Michael addition. In addition, optically pure 1-amino-3,4-diol is synthesized from 2-oxa-3-aza-bicycloketones. Use of p-phenoxynitrosobenzene allows access to protected amino diol via cleavage of the N-Ph bond.
本文介绍了使用烯胺对亚硝基狄尔斯-阿尔德型双环酮进行完全非对映和高对映选择性合成。通过大位阻联萘酚1c中两个羟基的氢键作用,在2-氧杂-3-氮杂双环酮的合成中实现了高对映选择性和完全非对映选择性。另一方面,α,β-不饱和酮可以用作二烯前体,利用易于获得的四唑催化剂3b,以中等产率和完全对映选择性提供3-氧杂-2-氮杂双环酮。对使用2-吗啉基-4,4-二苯基环己二烯2d的反应进行的研究清楚地表明,与大位阻联萘酚1c的环化参与了连续过程,即N-亚硝基羟醛反应,随后是迈克尔加成。此外,由2-氧杂-3-氮杂双环酮合成了光学纯的1-氨基-3,4-二醇。使用对苯氧基亚硝基苯可通过N-Ph键的裂解获得受保护的氨基二醇。