Alternative synthetic methodology for the direct installation of sulfonamide functionality is a highly desirable goal within the domain of drug discovery and development. The formation of synthetically valuable N-sulfonyl imines from a range of aldehydes, sulfonamides, and PhI(OAc)2 under practical and mild reaction conditions has been developed. According to mechanistic studies described within, the reaction
Asymmetric Friedel–Crafts addition of indoles to N-sulfonyl aldimines catalyzed by Cu(<scp>ii</scp>) chiral amino alcohol based Schiff base complexes
作者:Prathibha Kumari、Prasanta Kumar Bera、Noor-ul H. Khan、Rukhsana I. Kureshy、Sayed H. R. Abdi、Hari C. Bajaj
DOI:10.1039/c3cy00629h
日期:——
Recyclable copper(II) chiral amino alcohol based Schiff base complexes smoothly catalysed the Friedel–Crafts alkylation of indole with aryl aldimine in good yields (98%) and with enantioselectivities up to 97%. The effects of ligand structure, solvent, metal source and temperature on the reaction were also studied. The catalytic system worked very well several times retaining its performance. To understand
Enantio- and Diastereoselective Synthesis of Piperidines by Coupling of Four Components in a “One-Pot” Sequence Involving Diphenylprolinol Silyl Ether Mediated Michael Reaction
An efficient, asymmetric, four-component, one-potsynthesis of highly substituted piperidines with excellent diastereo- and enantioselectivity was established through the diphenylprolinol silyl ether mediated Michael reaction of aldehyde and nitroalkene, followed by the domino aza-Henry reaction/hemiaminalization reaction and a Lewis acid mediated allylation or cyanation reaction. All carbons of the
Hydroxyproline-Derived Pseudoenantiomeric [2.2.1] Bicyclic Phosphines: Asymmetric Synthesis of (+)- and (−)-Pyrrolines
作者:Christopher E. Henry、Qihai Xu、Yi Chiao Fan、Tioga J. Martin、Lee Belding、Travis Dudding、Ohyun Kwon
DOI:10.1021/ja505592h
日期:2014.8.27
We have prepared two new diastereoisomeric 2-aza-5-phosphabicyclo[2.2.1]heptanes from naturally occurring trans-4-hydroxy-l-proline in six chemical operations. These syntheses are concise and highly efficient, with straightforward purification. When we used these chiral phosphines as catalysts for reactions of γ-substituted allenoates with imines, we obtained enantiomerically enriched pyrrolines in