Copper(II)-Catalyzed Amidations of Alkynyl Bromides as a General Synthesis of Ynamides and Z-Enamides. An Intramolecular Amidation for the Synthesis of Macrocyclic Ynamides

Abstract

A general and efficient method for the coupling of a wide range of amides with alkynyl bromides is described here. This novel amidation reaction involves a catalytic protocol using copper(II) sulfate-pentahydrate and 1,10-phenanthroline to direct the sp-C-N bond formation, leading to a structurally diverse array of ynamides including macrocyclic ynamides via an intramolecular amidation. Given the surging interest in ynamide chemistry, this atom economical synthesis of ynamides should invoke further attention from the synthetic organic community.

A Useful, Reliable and Safer Protocol for Hydrogenation and the Hydrogenolysis ofO‐Benzyl Groups: The In Situ Preparation of an Active Pd0/C Catalyst with Well‐Defined Properties

“…Similar behaviour has already been observed with Lindlars catalyst. [10] To evaluate the added value of our in situ prepared catalyst, we evaluated (Table 3) the catalytic activity of various commercially available Pd/C catalysts for the reduction of cholesterol (15) to 5a-cholestan-3b-ol (16) at a Pd loading of 1 mol %. As expected, dramatic differences in catalytic activity are observed, depending upon the Pd source, giving low to good conversions.…”

Diamine ligands in copper-catalyzed reactions

“…86 Subsequently, Danheiser 87 and Hsung 88,89 have discovered alternative conditions which have served to increase the substrate scope. Recently Evano has documented a new method for the synthesis of ynamides from 1,1-dibromo-1-alkenes and sulfonamides or carbamates using a copper-diamine catalyst (Scheme 5).…”

Synthesis of 2-iodoynamides and regioselective [2+2] cycloadditions with ketene

“…Recent advances in our laboratory17 and that of Hsung18 have provided the basis for the efficient and convenient synthesis of a variety of ynamides. We have found these methods to be complementary, and both procedures were employed in the present study.…”