环亚胺的磺胺-施陶丁格环加成中的年环选择性和立体化学受环亚胺的环大小控制。本质上,环状亚胺的位阻控制环选择性,以及[2 s + 2 i + 2 i ]环中的立体化学。提出了一种逐步的[4 + 2]环化机理,其中包括分子间加成,CS键异构化以及随后的分子内加成,以解释[2 s + 2 i + 2 i]中的不同立体化学。]环行。分子间加成被认为是关键的立体确定步骤。首先,C3和C5的立体化学动力学由受控内切或外切加成亚胺到密钥两性离子2,3- thiaza -1,4-丁二烯型中间体,然后将C5和C6立体化学热力学由异构化控制前一步生成的两性离子内-或外-加合物中的C S键的位置。分子内添加不会影响[2 s + 2 i + 2 i ]环空的立体化学结果。
Sterically controlled diastereoselectivity in thio-Staudinger cycloadditions of alkyl/alkenyl/aryl-substituted thioketenes
作者:Wei He、Junpeng Zhuang、Zhanhui Yang、Jiaxi Xu
DOI:10.1039/c7ob01214d
日期:——
thioketenes and imines are named as thio-Staudinger cycloadditions. The diastereoselectivity in thio-Staudinger cycloaddtions of alkyl/alkenyl/aryl-substituted thioketenes is rationalized. The steric effects of the thioketenes play an extremely important role in deciding the diastereoselectivity (cis/trans selectivity) through controlling exo- and endo-attack and subsequent ring closure. The conclusion
Insights into the β-Sultam Ring Formation in the Sulfa-Staudinger Cycloadditions
作者:Zhanhui Yang、Jiaxi Xu
DOI:10.1021/jo5020933
日期:2014.11.7
The reaction of imines with sulfonyl chlorides or even direct sulfenes to form β-sultams is herein named as sulfa-Staudinger cycloaddition. The β-sultam formation is proposed to follow a stepwise mechanism of sulfonylation, deprotonation, and conrotatory ringclosure with 2,3-thiazabutadiene-type zwitterionic intermediates as key intermediates. Cyclic (Z)-imines give rise to trans-β-sultams exclusively
Synthesis of a Benzodiazepine-Derived Rhodium NHC Complex by C−H Bond Activation
作者:Michael W. Gribble、Jonathan A. Ellman、Robert G. Bergman
DOI:10.1021/om8000839
日期:2008.5.1
The synthesis and characterization of a Rh(I)-NHC complex generated by C-H activation of 1,4-benzodiazepine heterocycle are reported. This complex constitutes a rare example of a carbene tautomer of a 1,4-benzodiazepine aldimine stabilized by transition metal coordination and demonstrates the ability of the catalytically relevant RhCl(PCy(3))(2) fragment to induce NHC-forming tautomerization of heterocycles
CYCLOALKYL, LACTAM, LACTONE AND RELATED COMPOUNDS, PHARMACEUTICAL COMPOSITIONS COMPRISING SAME, AND METHODS FOR INHIBITING BETA-AMYLOID PEPTIDE RELEASE AND/OR ITS SYNTHESIS BY USE OF SUCH COMPOUNDS
申请人:Elan Pharmaceuticals, Inc.
公开号:EP0951466A2
公开(公告)日:1999-10-27
BENZODIAZEPINE DERIVATIVES, COMPOSITIONS CONTAINING THEM AND THEIR USE IN THERAPY