A Gold‐Catalyzed Acid‐Assisted Regioselective Cyclization for the Synthesis of Polysubstituted Oxazoles
作者:Qian Wang、Stephanie Hoffmann、Jasmin Schießl、Matthias Rudolph、Frank Rominger、A. Stephen K. Hashmi
DOI:10.1002/ejoc.201900699
日期:2020.5.3
derivatives are obtained through a regioselective gold‐catalyzed reaction of α‐alkynylamides and alkynoates in the presence of nitriles. The intermediary obtained gold carbenes are generated by an alkyne oxidation with a pyridine N‐oxide. Acidic conditions ensure that only one of the two carbonyl oxygen atoms in these intermediates selectively cyclizes to the products in excellent yields.
作者:Alexey Yu. Dubovtsev、Dmitry V. Dar'in、Vadim Yu. Kukushkin
DOI:10.1002/adsc.201900097
日期:2019.6.18
Three‐component [2+2+1] gold(I)‐catalyzed reaction of internalalkynes (alkynyl esters or ‐ketones), nitriles, and 2‐chloropyridine N‐oxide led to a wide range of fully substituted 1,3‐oxazoles (32 examples; up to 92% isolated yields). Nitrile R3CN species, employed in the reaction as both reactants and solvents, comprise conventional nitriles (R3=Alk, Ar) and also push‐pull systems such as cyanamides