Asymmetric cascades of the π-allyl complex: a journey from transition-metal catalysis to metallaphotocatalysis

Abstract

Enantioselective cascades involving the reaction of the π-allyl complex have been a viable strategy, and further replacement of the customary allyl acetates with contemporary synthons has opened many opportunities in this escalating field.

New Avenues for the Synthesis of Oxa‐Cycles Using Lewis/Brønsted Acid Mediated Carboxygenation and Carboalkoxylation of Alkynes

“…The past few decades have witnessed the emergence of cascade reactions as a powerful tool for the rapid and smooth construction of complex molecular architectures. [1][2][3][4][5][6][7][8] Among these, cascade functionalization of alkynes has offered many elegant and viable strategies for the synthesis of heterocyclic scaffolds, pharmacophores, and bio-active natural products. [9][10][11] These have mainly involved the generation of cascade CÀ C, CÀ O, CÀ N, CÀ S, and CÀ P bond formation under different chemical environments and have delivered access to the synthesis of many chemically challenging entities.…”

Electron Donor‐Acceptor (EDA) Complex Enabled C−C Cross‐Coupling Reactions of α‐Amino Radicals

“…[41] Later to make the process more economical, metallaphotocatalysis came front where a combination of visible light and transition metal was used to affect the catalytic cycle. [42,43] Though the synthetic value and utility were enhanced, the process was not ecofriendly because of the generated toxic metallic waste as one of the by-products. To overcome these deficiencies, photoredox catalysis was applied.…”

Transition metal catalysed cascade C–C and C–O bond forming events of alkynes

“…In addition to this significant utility of cascade processes in synthetic methodologies, these processes have been extensively used in the stereoselective and enantioselective total synthesis of complex natural products. [1][2][3][4][5][6][7][8][9][10] Alternatively, the existing dual nature (electrophilic and nucleophilic properties) of alkynes in a suitable reaction environment has made them valued synthons, and thus, alkynes have attracted significant attraction from the synthetic…”

“…In addition to this significant utility of cascade processes in synthetic methodologies, these processes have been extensively used in the stereoselective and enantioselective total synthesis of complex natural products. 1–10…”