Recently, carbonylation reactions have gained considerable interest as they are becoming a versatile tool in the synthesis of pharmaceuticals, agrochemicals and their intermediates. Nowadays, a plethora of transition metal catalysts are available for the synthesis of various functional groups like ureas, carbamates, oxamates, oxamides, α-keto amides, ketones, esters, etc. using carbonylation methodology. Several carbonylation reactions such as aminocarbonylation, alkoxycarbonylation, double carbonylation and oxidative carbonylation, provide efficient and attractive alternatives to the conventional synthetic routes on a laboratory or industrial scale. Oxidative carbonylation is an important reaction as it allows direct carbonylative C–H bond activation. A double carbonylation reaction provides a one step alternative route for the synthesis of α-keto amides, oxamides, and oxamates. It also eliminates the use of conventional thermally unstable and toxic reagents like oxalyl chloride. Several recent studies have focused on the various aspects of these reactions, including catalyst–product separation, and catalyst recoverability and reusability. In view of this, developments in anchoring homogeneous catalysts using various techniques like biphasic catalysis and supported liquid phase catalysis are gaining importance. Carbonylation routes using these techniques are simple, efficient, economical, avoid the use of ligands, and give the desired products in excellent yields. The use of phosphine ligands is disadvantageous as it leads to air/moisture sensitivity, tedious work-up procedures and high work-up costs. Several phosphine-free carbonylation routes eliminate the use of phosphine ligands, and provide economical and simple methods for these transformations. In this review we have summarized the recent trends in carbonylative transformations, which have undergone a rapid development.

Transition metal catalyzed carbonylation reactions using carbon monoxide as the C-1 source have occupied an all important position in catalysis which is subsequently related to organic synthesis and industrial synthesis of molecules. However, the use of carbon monoxide, an inflammable, toxic greenhouse gas acts as a deterrent to academic and industrial research. Hence, it is imperative to develop a CO-free protocol for promoting sustainable chemistry. The chemistry of CO surrogates has undergone substantial progress with the development of newer reaction methodologies and newer surrogate molecules. Aldehydes, formate esters, formamides, and metal carbonyls have been applied not only to the synthesis of industrial bulk chemicals, but also to the synthesis of specialty chemicals and molecules which are important pharmacological building blocks. Simultaneous development of a two-chamber reactor allows for the ex situ generation of CO and hence circumvents the compatibility issues associated with the substrate and the surrogate during in situ CO generation. Further, the development of specialized surrogate molecules allows for the incorporation of ¹³C and ¹⁴C-labelled isotopes even at an advanced stage of the synthesis of the molecules. This review thus summarizes the progress in the past decade in the development of synthetic methodologies in which carbonylation reactions are carried out without the use of gaseous carbon monoxide or using carbon monoxide surrogates.