Dihydrooxazine Oxides as Key Intermediates in Organocatalytic Michael Additions of Aldehydes to Nitroalkenes
作者:Gokarneswar Sahoo、Hasibur Rahaman、Ádám Madarász、Imre Pápai、Mikko Melarto、Arto Valkonen、Petri M. Pihko
DOI:10.1002/anie.201204833
日期:2012.12.21
Pause and play: Dihydrooxazine oxides are stable intermediates that are protonated directly, without the intermediacy of the zwitterions, in organocatalytic Michael additions of aldehydes and nitroalkenes (see scheme, R=alkyl). Protonation of these species explains both the role of the acid co‐catalyst in these reactions, and the observed stereochemistry when the reaction is conducted with α‐alkylnitroalkenes
暂停和游戏:二氢恶嗪氧化物是稳定的中间体,可在醛和硝基烯的有机催化迈克尔加成反应中,直接在不带两性离子的情况下进行质子化(请参阅方案,R =烷基)。这些物质的质子化解释了酸助催化剂在这些反应中的作用,以及与α-烷基硝基烯烃进行反应时观察到的立体化学。