Sustainable Amine Synthesis: Iron Catalyzed Reactions of Hydrosilanes with Imines, Amides, Nitroarenes and Nitriles

Abstract

Iron catalyzed organic synthesis has emerged as a sustainable chemistry due to the highly competitive cost, high natural abundance and ecologically acceptable properties of iron. Moreover, its extensive range of oxidation states i. e. -II to + VI provides numerous opportunities to perform multiple organic reactions. Recently iron catalysis has started competing the established precious metals. Among organic scaffolds, amines are important building blocks that are useful in the various fields starting from drugs, crop protection chemicals to dyes and pigments. Typically, hydrogenation or reduction of functional groups such as imines, amides, nitroarenes and nitriles results into amines. In this context, homogeneous iron catalyzed hydrosilylation is a highly promising alternative to traditional hydrogenation and other reduction reactions. This review is focused on the synthesis of amine and its derivatives via hydrosilylation of imines, amides, nitroarenes and nitriles using iron as a catalyst. Some of the reduction methods of these functional groups that may not follow the typical hydrosilylation pathway are also included in this review due to their strong relevance to the theme. The phenomenal progress in this focused area is summarized to witness this transformation towards sustainable development in the field of amine synthesis.

Hydroelementation of diynes

“…Hydroelementation reactions are one of the most prominent transformations in organic and organometallic chemistry, to obtain functionalised compounds from the addition of E-H bonds (E = Mg, B, Al, Si, Ge, Sn, N, P, O, S, Se, Te) to unsaturated C-C bonds in olefins (CQC) or alkynes (CRC), C-N bonds in imines (CQN) 2,[32][33][34][35][36] or nitriles (CRN), 2,33,34,37 and CQO bonds in carbonyl compounds. 2,[32][33][34][35][38][39][40][41][42][43][44][45][46][47] The processes are mostly catalytic but may also occur as uncatalysed. In both cases, the stereo-and regioselectivity of the reaction depends upon the catalyst, reagent, and reaction conditions.…”

Catalytic Nitrile Hydroboration: A Route to N,N‐Diborylamines and Uses Thereof

“…[14,15] Ever since a plethora of catalytic hydrosilylation methods have been developed based on precious and base metals, as well as metal-free systems. [16][17][18] In contrast, nitrile hydroboration, catalyzed by a Mo(IV) complex was first reported in 2012 [19] and up to date catalytic systems for efficient and mild hydroboration of nitriles are relatively scarce.…”

Terpyridine–Ru Complexes Noncovalently Supported on Cobalt Magnetic Nanoparticles for Nitroarene Transfer Hydrogenation

“…One aim of this work was to design related systems enabling reversible interactions in organic media and, in particular, in 2-propanol, a cheap, benign, and easy-to-handle H source employed in transfer hydrogenations of various substrates . Among the latter, nitroarenes give rise to anilines, key compounds finding widespread applications as intermediates and targets in pharmaceutical, agrochemical, pigment, or dye industries and holding a very high market share in the organic chemistry industry . In general, the use of H-donors instead of molecular hydrogen for nitroarene reduction enables to avoid high-pressure equipments.…”