Copper(II)‐Catalyzed Aminohalogenation of Alkynyl Carbamates

Abstract

A useful aminohalogenation reaction for the cyclization of O‐alkynyl carbamates under copper catalysis has been developed. N‐Halosuccinimides have been used as a halogen source. The intramolecular C−N bond formation occurs selectively affording haloalkylidene substituted heterocycles. Just in the case of α,α‐cyclohexyl‐substituted propargyl carbamate, the alkoxyhalogenation pathway was operative. The mechanism for the two alternative reaction pathways was investigated by modeling the corresponding transition states at the DFT level.

Metal‐Free One‐Pot Domino Synthesis of Oxazolidinone Derivatives

“…Recently, Beccalli and co‐workers reported the reaction of O‐alkynyl carbamates using NXS and in presence of CuCl 2 under heating condition forms the haloalkylidene substituted heterocycles was developed in acetonitrile solvent [5e] (Scheme 2).…”

A Non‐coded β2,2‐Amino Acid with Isoxazoline Core Able to Stabilize Peptides Folding through an Unprecedented Hydrogen Bond

“…[45] To confirm the presence and evaluate the strength of such intramolecular interactions, we performed a Quantum Theory Atom in Molecules (QTAIM) analysis on the DFT-optimized 8a-C11 geometry. [46] Indeed, QTAIM has been successfully used to characterize both intermolecular [47,48] and intramolecular non-covalent interaction, [49] including classic and weak H-bonds in peptides. [45,50] An H-bond, as well as all covalent and non-covalent interactions, can be described by a bond path (BP) and a bond critical point (BCP).…”

Recent Advances in Nonprecious Metal Catalysis

“…Beccalli and co-workers reported a convenient Cu-catalyzed method for the preparation of haloalkylidene-substituted heterocycles (Scheme 43), 106 inspired by previous reports on aminohalogenation of O-propargyl carbamates. REPORTS ON FE-CATALYZED REACTIONS Meggers and co-workers reported a highly efficient Fecatalyzed intramolecular amination of C(sp 3 )−H bonds in Nbenzoyloxyurea to form imidazolidin-2-ones (Scheme 44).…”

“…Beccalli and co-workers reported a convenient Cu-catalyzed method for the preparation of haloalkylidene-substituted heterocycles (Scheme ), inspired by previous reports on aminohalogenation of O -propargyl carbamates. − The heterocycles were formed exclusively with E selectivity. The reaction was proposed to proceed via activation of the alkyne by Cu toward intramolecular nucleophilic attack by N to generate a vinylcopper intermediate, which reacts with N -halosuccinimide to generate the product.…”