Department of Chemistry, National Taiwan Normal University , Taipei 11677, Taiwan R.O.C.
Org Lett. 2016 Jul 1;18(13):3046-9. doi: 10.1021/acs.orglett.6b00493. Epub 2016 Jun 9.
Kinetic resolution of nitroallylic amines was established using chiral α,α-l-diphenylprolinol silyl ether auxiliary through isolation of the dihydrooxazine N-oxide intermediates. Further hydrolyzing the resting states provided tetrahydropyridines in high chemical yields and high to excellent stereoselectivities (up to >20:1 dr and 98% ee). A detailed mechanistic explanation for stereoselective protonation in the dihydrooxazine was probed computationally. In addition, the probable intermediates in α-halogenation of aldehydes (masked with enamines) were isolated to provide crystallographic evidence.
通过手性 α,α-二苯基脯氨醇硅醚辅助物对硝基烯丙基胺进行动力学拆分，通过分离二氢恶嗪 N-氧化物中间体来实现。进一步水解反应中间体得到四氢吡啶，具有高化学产率和高至优异的立体选择性（高达>20:1dr 和 98%ee）。通过计算对二氢恶嗪中立体选择性质子化进行了详细的机理探究。此外，还分离出了醛（经烯胺保护）的α-卤化的可能中间体，为反应提供了晶体学证据。
