Department of Chemistry, Nanoscience Center, University of Jyväskylä, Finland.
Angew Chem Int Ed Engl. 2012 Dec 21;51(52):13144-8. doi: 10.1002/anie.201204833. Epub 2012 Nov 13.
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.
二氢恶嗪氧化物是稳定的中间体，可直接质子化，而无需经历两性离子中间体，在醛和硝基烯烃的有机催化迈克尔加成反应中（参见方案，R=烷基）。这些物种的质子化解释了在这些反应中酸助催化剂的作用，以及当反应与α-烷基硝基烯烃进行时观察到的立体化学。
