A Versatile Room-Temperature Route to Di- and Trisubstituted Allenes Using Flow-Generated Diazo Compounds
作者:Jian-Siang Poh、Duc N. Tran、Claudio Battilocchio、Joel M. Hawkins、Steven V. Ley
DOI:10.1002/anie.201501538
日期:2015.6.26
A copper‐catalyzed coupling reaction between flow‐generated unstabilized diazocompounds and terminal alkynes provides di‐ and trisubstitutedallenes. This extremely mild and rapid transformation is highly tolerant of several functional groups.
Access to N-Substituted 2-Pyridones by Catalytic Intermolecular Dearomatization and 1,4-Acyl Transfer
作者:Guangyang Xu、Ping Chen、Pei Liu、Shengbiao Tang、Xinhao Zhang、Jiangtao Sun
DOI:10.1002/anie.201812937
日期:2019.2.11
A novel rhodium‐catalyzed dearomatization of O‐substituted pyridines to access N‐substituted 2‐pyridones has been developed. A computational study suggests a mechanism involving the formation of a pyridinium ylide followed by an unprecedented 1,4‐acyl migratory rearrangement from O to C. Furthermore, the chiral dirhodium complexes serve as the catalyst for the asymmetric transformation with excellent
Synthesis of Acyclic Ketones by Catalytic, Bidirectional Homologation of Formaldehyde with Nonstabilized Diazoalkanes. Application of a Chiral Diazomethyl(pyrrolidine) in Total Syntheses of Erythroxylon Alkaloids
作者:Andrew J. Wommack、Jason S. Kingsbury
DOI:10.1021/jo401377a
日期:2013.11.1
This work offers a catalytic approach to convergent ketone assembly based upon formal and tandem C–H insertion of diazoalkanes in the presence of limiting amounts of monomeric formaldehyde, which is easily generated as a gas by thermolysis of the inexpensive and abundant paraformaldehyde (∼30 USD/kg). The method forms di-, tri-, and even tetrasubstituted acetones with high efficiency, and it has streamlined
Titration of Nonstabilized Diazoalkane Solutions by Fluorine NMR
作者:Victor L. Rendina、Jason S. Kingsbury
DOI:10.1021/jo202214e
日期:2012.1.20
A new protocol for titrating nonstabilized diazoalkane solutions by quantitative 19F NMR is reported. An excess of 2-fluorobenzoic acid dissolved in CDCl3 is treated with the diazoalkane solution at a low temperature, immediately forming the corresponding 2-fluorobenzoate ester upon warming. A significant difference in the 19F chemical shift between the ester and acid is seen, allowing facile and accurate
报道了通过定量19 F NMR滴定不稳定的重氮烷溶液的新方案。用重氮烷溶液在低温下处理溶解在CDCl 3中的过量的2-氟苯甲酸,在加热后立即形成相应的2-氟苯甲酸酯。观察到酯和酸之间在19 F化学位移方面存在显着差异,从而可以轻松,准确地积分来确定滴度。该过程安全,快速,并且可以高精度指示活性重氮烷浓度。