Recent Advances in Organocatalyzed Domino C–C Bond-Forming Reactions

Abstract

Reactions that form a C–C bond make up a foundational pillar of synthetic organic chemistry. In addition, organocatalysis has emerged as an easy, environmentally-friendly way to promote this type of bond formation. Since around 2000, organocatalysts have been used in a variety of C–C bond-forming reactions including Michael and aldol additions, Mannich-type reactions, and Diels–Alder reactions, to name a few. Many of these methodologies have been refined and further developed to include cascade and domino processes. This review will focus on recent advances in this area with an emphasis on methodologies having applications in the synthesis of biologically-significant compounds.

Caged Proline in Photoinitiated Organocatalysis

“…1 H NMR (400 MHz, CDCl 3 ) δ 8.22 (d, J = 7.9 Hz, 2H), 7.54 (d, J = 8.1 Hz, 2H), 5.34−5.20 (m, 1H), 3.56 (s, 1H), 2.85 (d, J = 7.5 Hz, 2H), 2.20 (d, J = 21.5 Hz, 3H). 13 (11). The photoactivatable catalyst 1 (76 mg, 0.2 mmol) was stirred in 8 mL of DMSO, p-anisidine (135 mg, 1.1 mmol), 4-nitrobenzaldehyde (151.12 mg, 1.0 mmol), and 2 mL of acetone in a 25 mL round-bottomed flask in the dark at rt.…”

“…Catalysts that can be activated upon demand are useful tools for multiple applications, especially in recent years alongside the growth of the field of bioorthogonal chemistry. , There are multiple types of triggers that include physical, chemical, biological, as well as mechanical forces. − However, triggering pathways using light has shown numerous advantages primarily due to the ability to precisely control the location and time of activation, generally referred to as spatiotemporal control . Organocatalysts have emerged as biomimetic catalysts, displaying advantages of being both greener as well as biocompatible. − The simple amino acid, proline, has been shown by several groups to be among the simplest and most efficient organocatalyst. − …”

Microwave assisted L‐proline catalyzed one‐pot three–component reaction for the synthesis of 4‐aminoaryl‐2‐phenyl‐2H‐3‐nitrochromene hybrid via Domino Michael‐Henry‐Michael addition reaction

“…3‐Nitro‐2 H ‐chromene (3‐nitro‐2 H ‐1‐benzopyran) is an oxygen containing heterocyclic compound, with benzopyran skeletal, found in numerous natural products including vegetables and fruits [1]. Among all the chromene derivatives, 2‐aryl‐3‐nitro‐2 H ‐chromenes are most important because they are highly reactive and related to conjugated nitro alkenes in chemical properties [2]. However, 2‐aryl‐3‐nitro‐2 H ‐chromene and 2,3,4 trisubstituted chromene are the most important precursor for the synthesis of various bioactive molecules, functional materials and natural products [3].…”

Development of Nitrolactonization Mediated by Iron(III) Nitrate Nonahydrate

“…Nitro compounds are useful synthons in synthetic organic chemistry due to their availability for various transformations. The strong electron-withdrawing property of the nitro group plays an important role in C-C bond formation reactions 1,2) including the nitro-aldol reaction (Henry reaction), [3][4][5] Michael reaction, [6][7][8][9][10][11] and alkylation. 12,13) Nitrones and nitrile oxides generated from nitro compounds undergo 1,3-dipole cycloaddition reaction to give various heterocycles.…”