Radical Cyclization of Trichloroacetamides: Synthesis of Lactams

Abstract

Trichloroacetamides can act as radical precursors to synthesize nitrogen-containing heterocycles in a variety of processes, mainly involving atom transfer radical cyclizations (ATRC), mediated by Cu(I) or Ru(II) catalysts, and the hydride reductive method, employing either Bu 3 SnH or (Me 3 Si) 3 SiH, or recently NaBH 3 CN. Additionally, amine-mediated single-electron transfer cyclizations, as well as radical processes promoted by Ni, Fe, Mn, Ti, and Ag, have been developed. 1 Introduction 2 Atom Transfer Radical Cyclizations (ATRC) 2.

Synthesis of the ABC Core of Daphniphyllum Alkaloids with a [5–6–7] Azatricyclic Scaffold via Ring Expansion of Azabicyclic and Azatricyclic Building Blocks

“…Initially, we decided to study the unprecedented carbocyclic ring expansion of morphan compounds from ketones 5 and 8 (series a–c) employing diazo derivative reagents, evaluating the regioselectivity of the Tiffeneau–Demjanov procedure, as well as the influence of the nitrogen atom functionality (amine, lactam, or carbamate) on the overall process (Scheme ). The required morphans were prepared following the methodology developed by our group as outlined in Scheme …”

“…The required morphans were prepared following the methodology developed by our group as outlined in Scheme 4. 15 Scheme 1. Precedents for the Synthesis of the ABC [7,6,5] The results reported here constitute a new approach to the synthesis of B-homomorphans.…”

Radical Cyclization-Initiated Difunctionalization Reactions of Alkenes and Alkynes

“…The reaction of allylamines or acryl-amides 350, alkylzinc or arylzinc bromides, Ni(Py) 4 Cl 2 and (S)-s-Bu(PyBox) in THF at room temperature for 16 h afforded pyrrolidines and pyrrolidinones 351 in good yields (Scheme 72) [97]. In this reaction, [RNi I L n ] complexes 352 produced by the reaction of Ni(py) 4 In 2022, Cárdenas and coworkers reported a Ni-catalyzed radical reaction of allylamines and acryl-amides containing an active ester group for the synthesis of nitrogen heterocycles. The reaction of allylamines or acryl-amides 350, alkylzinc or arylzinc bromides, Ni(Py)4Cl2 and (S)-s-Bu(PyBox) in THF at room temperature for 16 h afforded pyrrolidines and pyrrolidinones 351 in good yields (Scheme 72) [97].…”

“…Feasible radical transformations including addition, cyclization, coupling, atom or group transfer, rearrangement, and fragmentation reactions have made radical reactions a powerful tool for making carbon-carbon and carbon-heteroatom bonds [ 1 , 2 ]. The recent developments in radical cyclative functionalization [ 3 , 4 ], radical-enabled bicyclization [ 5 ], photoredox reactions [ 6 , 7 , 8 ], mechanoredox reactions [ 9 ], electrochemical reactions [ 10 ], and transition metal-assisted radical reactions [ 11 , 12 , 13 , 14 ] have empowered the utility of synthetic radicals. Radical reactions being performed in a cascade sequence for the assembling of complex molecular scaffolds with multiple functional groups in regio- and diastereoselective manners is a unique feature.…”

Radical Cyclization-initiated Difunctionalization Reactions of Alkenes and Alkynes

“…Feasible radical transformations including addition, cyclization, coupling, atom or group transfer, rearrangement, and fragmentation reactions have made radical reactions a powerful tool for making carbon-carbon and carbon-heteroatom bonds [1,2]. The recent development on radical cyclative functionalization [3,4], radical-enabled bicyclization [5], photoredox reactions [6][7][8], mechanoredox reactions [9], electrochemical reactions [10], and transition metal-assisted radical reactions [11][12][13][14] have empowered the utility of synthetic radicals. It is a unique feature that radical reactions could be performed in a cascade sequence for the assembling of complex molecular scaffolds with multiple functional groups in regio-and diastereoselective manners.…”