Organocatalysis in the Asymmetric Synthesis of Nitrogen-Containing Compounds: How and Why

Abstract

Various types of polyfunctionalised stereodefined organic molecules appear to be highly serviceable as organocatalysts in the asymmetric synthesis of nitrogen-containing compounds. Beyond name reactions such as the aza-Henry, the Friedel-Crafts, and the Strecker other representative transformations like the hydrophosphonylation can be easily approached by using the suitable organocatalytic species and are herein reported with a special emphasis placed on the reaction and stereochemical outcomes and on the mechanistic insights

Nitro-Mannich Reaction

“…Small molecule organocatalysis has emerged as an extremely powerful tool for asymmetric synthesis and been successfully applied to a whole host of C–C bond-forming processes. − Consequently, a number of different organocatalysts have been developed for use in nitro-Mannich reactions. These include a variety of different chiral thioureas, Brønsted acids, and phase-transfers catalysts that are able to catalyze highly stereoselective reactions.…”

“…Although the nitro-Mannich reaction has not previously been reviewed in its entirety, selected aspects of this reaction have appeared in reviews on related subjects. These include reviews on multimetallic multifunctional catalysts, − asymmetric additions to CN bonds, − organocatalysis, − N -acyl imines, and synthesis of α,β-diamino acids . There have also been a number of smaller reviews that have focused specifically on asymmetric nitro-Mannich reactions. , The most recent of these was in 2009 and contains a good review of the asymmetric methodology up to that point .…”

Michael Addition of Manganese Enolates to Nitroolefins

“…The well-known capability of certain double bonding hydrogen donors to interact with the NO 2 function, increasing its electron-withdrawing power, 8 and our ongoing interest in organocatalysis, 9 prompted us to investigate the effect of the simple thiourea-based system A (Figure 3) in this reaction. This attempt was made on the assumption that due to the strong affinity of Mn towards oxygen, the Mn-O bond in manganese enolates might not be quenched by the NH protons (pK a = 21).…”