Asymmetric hydrolytic kinetic resolution with recyclable polymeric Co(<scp>iii</scp>)–salen complexes: a practical strategy in the preparation of (S)-metoprolol, (S)-toliprolol and (S)-alprenolol: computational rationale for enantioselectivity
作者:Tamal Roy、Sunirmal Barik、Manish Kumar、Rukhsana I. Kureshy、Bishwajit Ganguly、Noor-ul H. Khan、Sayed H. R. Abdi、Hari C. Bajaj
DOI:10.1039/c4cy00594e
日期:——
epoxide (up to 46% compared to 50% theoretical yield) along with high enantioselectivity (up to 99%) were obtained in most cases using catalyst 1. Further studies showed that catalyst 1 could retain its catalyticactivity for six cycles under the present reaction conditions without any significant loss in activity or enantioselectivity. To show the practical applicability of the above synthesized catalyst
Dimerization and Isomerization Reactions of α-Lithiated Terminal Aziridines
作者:David M. Hodgson、Philip G. Humphreys、Steven M. Miles、Christopher A. J. Brierley、John G. Ward
DOI:10.1021/jo701901t
日期:2007.12.1
The scope of dimerization and isomerization reactions of α-lithiated terminal aziridines is detailed. Regio- and stereoselective deprotonation of simple terminal aziridines with lithium 2,2,6,6-tetramethylpiperidide (LTMP) or lithium dicyclohexylamide (LiNCy2) generates trans-α-lithiated terminal aziridines. These latter species can then undergo dimerization or isomerization reactions depending on
Direct Access to 2,3,4,6-Tetrasubstituted Tetrahydro-2<i>H</i>-pyrans via Tandem S<sub>N</sub>2′–Prins Cyclization
作者:Jimena Scoccia、Sixto J. Pérez、Victoria Sinka、Daniel A. Cruz、Juan M. López-Soria、Israel Fernández、Víctor S. Martín、Pedro O. Miranda、Juan I. Padrón
DOI:10.1021/acs.orglett.7b02270
日期:2017.9.15
reaction, iron(III) catalyzed an SN2′–Prins cyclization tandem process leading to the creation of three new stereocenters in one single step. These activated tetrahydro-2H-pyran units are easily derivatizable through CuAAC conjugations in order to generate multifunctionalized complex molecules. DFT calculations support the in situ SN2′ reaction as a preliminary step in the Prins cyclization.
描述了活化的2,3,4,6-四取代的四氢-2 H-吡喃的新的,直接的和非对映选择性的合成。在该反应中,铁(III)催化了一个S N 2'-Prins环化串联过程,从而一步就可以生成三个新的立体中心。这些活化的四氢-2 H-吡喃单元很容易通过CuAAC共轭衍生,以生成多功能复合分子。DFT计算支持原位S N 2'反应,作为Prins环化的第一步。
Synthesis of sp3-rich chemical libraries based upon 1,2-diazetidines
作者:Conor Dean、Stefan Roesner、Sundaram Rajkumar、Guy J. Clarkson、Matthew Jones、Michael Shipman
DOI:10.1016/j.tet.2020.131836
日期:2021.1
is described. Stereocontrolledring opening of homochiral 1,2-epoxides by hydrazine monohydrate followed by selective protection of both nitrogen atoms and Mitsunobu ring closure gives differentially protected, enantiomerically pure 1,2-diazetidines (up to 98% ee) bearing a variety of C-3 substituents. Iterative C–N functionalization at the two nitrogen atoms using a range of chemistries and coupling