Catalytic Radical Domino Reactions in Organic Synthesis

Abstract

Catalytic radical-based domino reactions represent important advances in synthetic organic chemistry. Their development benefits synthesis by providing atom- and step-economical methods to complex molecules. Intricate combinations of radical, cationic, anionic, oxidative/reductive, and transition metal mechanistic steps result in cyclizations, additions, fragmentations, ring-expansions, and rearrangements. This Perspective summarizes recent developments in the field of catalytic domino processes.

Auto‐Tandem Catalysis: Activation of Multiple, Mechanistically Distinct Process by a Single Catalyst

“…The catalysis of multiple, mechanistically distinct processes in a synthetic sequences was defined by Fogg and dos Santos as auto‐tandem catalysis (Figure ) , . Whilst this process has been described by a number of different names through the years, such as: (a) single‐pot catalysis, (b) domino‐catalysis, (c) one‐pot catalysis, (d) tandem‐catalysis, (e) dual catalysis and (f) multifaceted catalysis, the emphasis on the development of novel, convergent synthetic methods has remained consistent. ATC is a powerful approach towards the synthesis of heterocycles and carbocycles as well as acyclic compounds.…”

Catalytic N-radical cascade reaction of hydrazones by oxidative deprotonation electron transfer and TEMPO mediation

“…Radical reactions, especially the radical cascades, provide a potential access to such ideal transformations and have attracted considerable attention of synthetic community because of their typically mild conditions, short reaction times and high efficiency 1 2 . Although various carbon radicals have been widely used in catalytic radical-based cascade reactions 3 4 5 , however, the chemistry of N-centred radicals in this regard remains largely unexplored because of a lack of convenient and general methods for their generation 6 7 . Known methods for their generation typically require the use of N-functionalized precursors or various toxic, potentially explosive or unstable radical initiators.…”

Towards the development of highly active copper catalysts for atom transfer radical addition (ATRA) and polymerization (ATRP)‡

“…Over the past five years, catalyst regeneration in ATRA has attracted considerable academic interest (Blackman, 2008;Díaz-Álvarez et al, 2008;Eckenhoff & Pintauer, 2010a;Iizuka et al, 2007;Lundgren et al, 2008;Maiti et al, 2008;Oe & Uozumi, 2008;Pintauer, 2010;Thommes et al, 2007;Wallentin et al, 2012;Wolf et al, 2008) and was successfully applied to intramolecular ATRA or atom transfer radical cyclization (ATRC) and sequential ATRA followed by [3+2] azide-alkyne cycloaddition reactions (Clark & Wilson, 2008;Muñoz-Molina et al, 2008;Nguyen et al, 2011;Sebren et al, 2014;Thommes et al, 2007;Wolf et al, 2008).…”