Synthesis of Nonracemic 1,4-Benzoxazines via Ring Opening/Cyclization of Activated Aziridines with 2-Halophenols: Formal Synthesis of Levofloxacin
作者:Abhijit Mal、Imtiyaz Ahmad Wani、Gaurav Goswami、Manas K. Ghorai
DOI:10.1021/acs.joc.8b00788
日期:2018.8.3
under one-pot conditions to furnish the 3,4-dihydro-1,4-benzoxazine derivatives in excellent yields (up to 95%). The strategy offers a short and efficient synthesis to (S)-3-methyl-1,4-benzoxazine (S)-3v, a late stage intermediate in the synthesis of levofloxacin.
已经通过一种有效且简单的方法以优异的对映体和非对映体特异性(ee> 99%,de> 99%)合成了新型3,4-二氢-1,4-苯并恶嗪衍生物。反应通过路易斯酸催化活化氮丙啶与2-卤代苯酚的S N 2型开环,然后在一锅条件下逐步进行Cu(I)催化的分子内C–N环化以提供3,4。 -二氢-1,4-苯并恶嗪衍生物,收率极高(高达95%)。该策略提供了短而有效的合成(S)-3-甲基-1,4-苯并恶嗪(S)-3v的方法,后者是左氧氟沙星合成的后期中间体。
A Synthetic Route to Chiral 1,4-Disubstituted Tetrahydro-β-Carbolines via Domino Ring-Opening Cyclization of Activated Aziridines with 2-Vinylindoles
作者:Masthanvali Sayyad、Imtiyaz Ahmad Wani、Raja Babu、Yerramsetti Nanaji、Manas K. Ghorai
DOI:10.1021/acs.joc.6b02719
日期:2017.3.3
for the synthesis of various 1,4-disubstituted tetrahydro-β-carbolines with excellent stereoselectivity (de, ee up to >99%) via domino ring opening cyclization (DROC) of activated aziridines with 2-vinylindoles is described. The reaction proceeds through LiClO4-catalyzed Friedel–Crafts-type alkylation of 2-vinylindoles with activated aziridines followed by an intramolecular aza-Michael reaction in a domino
A Synthetic Route to Chiral Tetrahydropyrroloindoles via Ring Opening of Activated Aziridines with 2-Bromoindoles Followed by Copper-Catalyzed C–N Cyclization
作者:Masthanvali Sayyad、Abhijit Mal、Imtiyaz Ahmad Wani、Manas K. Ghorai
DOI:10.1021/acs.joc.6b01049
日期:2016.8.5
A new syntheticroute to nonracemic tetrahydropyrrolo[2,3-b]indoles has been developed via SN2-type ringopening of enantiopure N-activated aziridines with 2-bromoindoles followed by copper-catalyzed C–Ncyclization. A series of N-activated aziridines and 2-bromoindole derivatives with different substitution patterns were studied to afford the corresponding tetrahydropyrrolo[2,3-b]indoles in good yields
通过用2-溴吲哚将对映纯N活化的氮丙啶的S N 2型开环,然后进行铜催化的CN环化,已开发出一种新的合成非外消旋四氢吡咯并[2,3- b ]吲哚的途径。研究了一系列具有不同取代模式的N活化氮丙啶和2-溴吲哚衍生物,从而以良好的收率和优异的ee(高达99%)提供了相应的四氢吡咯并[2,3- b ]吲哚。高度取代的四氢吡咯并[2,3- b ]吲哚由对映体纯的反式-二取代的氮丙啶合成为单个立体异构体(de,ee> 99%)。
Stereospecific Assembly of Fused Imidazolidines via Tandem Ring Opening/Oxidative Amination of Aziridines with Cyclic Secondary Amines Using Photoredox Catalysis
Sustainable assembly of imidazolidines is accomplished via a sequential stereospecific ringopening and C–H amination using aziridines with secondary cyclic amines under visible light mediated indazoloquinoline photoredox catalysis at ambient conditions. Optically active aziridines are coupled with high enantiomeric purities. The computational studies provide insights on the redox properties of the
Stereospecific Synthesis of 2-Iminothiazolidines via Domino Ring-Opening Cyclization of Activated Aziridines with Aryl- and Alkyl Isothiocyanates
作者:Aditya Bhattacharyya、C. V. Kavitha、Manas K. Ghorai
DOI:10.1021/acs.joc.6b01551
日期:2016.8.5
catalyzed domino ring-opening cyclization of activated aziridines with aryl and alkyl isothiocyanates has been accomplished leading to the formation of a wide variety of highly substituted and functionalized 2-iminothiazolidines with excellent diastereo- and enantiospecificity (de, ee up to >99%). The reaction proceeds via a Lewis acid catalyzed SN2-type ring-opening of the activated aziridine followed by
用芳基和异硫氰酸烷基酯完成路易斯酸催化活化氮丙啶的多米诺环的开环反应,导致形成各种具有高度非对映体和对映体特异性的高取代和官能化的2-亚氨基噻唑烷(de,ee可达> 99% )。反应是通过路易斯酸催化的活化氮丙啶的S N 2型开环进行的,然后以多米诺方式同时进行5- exo-dig环化反应,以极高的收率(高达99%)提供2-iminothiazolidine衍生物。 。