Santanu Mukherjee

Bio: Santanu Mukherjee is an academic researcher from Indian Institute of Science. The author has contributed to research in topics: Enantioselective synthesis & Desymmetrization. The author has an hindex of 29, co-authored 93 publications receiving 5002 citations. Previous affiliations of Santanu Mukherjee include Harvard University & Max Planck Society.

Chiral counteranions in asymmetric transition-metal catalysis: Highly enantioselective Pd/Brønsted acid-catalyzed direct α-allylation of aldehydes

Abstract: We have developed a highly enantioselective Pd/chiral acid-catalyzed α-allylation of α-branched aldehydes with an allyl amine as the allylating species that creates all-carbon quaternary stereogenic centers in high yields and enantioselectivities. To our knowledge, this is the first time that a chiral anionic ligand is applied for achieving asymmetric induction in a palladium-catalyzed allylic alkylation reaction.

Visible Light Photoredox Catalysis with Transition Metal Complexes: Applications in Organic Synthesis

Abstract: A fundamental aim in the field of catalysis is the development of new modes of small molecule activation. One approach toward the catalytic activation of organic molecules that has received much attention recently is visible light photoredox catalysis. In a general sense, this approach relies on the ability of metal complexes and organic dyes to engage in single-electron-transfer (SET) processes with organic substrates upon photoexcitation with visible light. Many of the most commonly employed visible light photocatalysts are polypyridyl complexes of ruthenium and iridium, and are typified by the complex tris(2,2′-bipyridine) ruthenium(II), or Ru(bpy)32+ (Figure 1). These complexes absorb light in the visible region of the electromagnetic spectrum to give stable, long-lived photoexcited states.1,2 The lifetime of the excited species is sufficiently long (1100 ns for Ru(bpy)32+) that it may engage in bimolecular electron-transfer reactions in competition with deactivation pathways.3 Although these species are poor single-electron oxidants and reductants in the ground state, excitation of an electron affords excited states that are very potent single-electron-transfer reagents. Importantly, the conversion of these bench stable, benign catalysts to redox-active species upon irradiation with simple household lightbulbs represents a remarkably chemoselective trigger to induce unique and valuable catalytic processes. Open in a separate window Figure 1 Ruthenium polypyridyl complexes: versatile visible light photocatalysts.

Mechanochemistry: opportunities for new and cleaner synthesis

Abstract: The aim of this critical review is to provide a broad but digestible overview of mechanochemical synthesis, i.e. reactions conducted by grinding solid reactants together with no or minimal solvent. Although mechanochemistry has historically been a sideline approach to synthesis it may soon move into the mainstream because it is increasingly apparent that it can be practical, and even advantageous, and because of the opportunities it provides for developing more sustainable methods. Concentrating on recent advances, this article covers industrial aspects, inorganic materials, organic synthesis, cocrystallisation, pharmaceutical aspects, metal complexes (including metal–organic frameworks), supramolecular aspects and characterization methods. The historical development, mechanistic aspects, limitations and opportunities are also discussed (314 references).

The advent and development of organocatalysis

Abstract: The use of small organic molecules as catalysts has been known for more than a century. But only in the past decade has organocatalysis become a thriving area of general concepts and widely applicable asymmetric reactions. Here I present my opinion on why the field of organocatalysis has blossomed so dramatically over the past decade.

Solar Synthesis: Prospects in Visible Light Photocatalysis

Abstract: Background Interest in photochemical synthesis has been motivated in part by the realization that sunlight is effectively an inexhaustible energy source.Chemists have also long recognized distinctive patterns of reactivity that are uniquely accessible via photochemical activation. However, most simple organic molecules absorb only ultraviolet (UV) light and cannot be activated by the visible wavelengths that comprise most of the solar energy that reaches Earth’s surface. Consequently, organic photochemistry has generally required the use of UV light sources. Visible light photocatalysis. ( A ) Transition metal photocatalysts, such as Ru(bpy) 3 2+ , readily absorb visible light to access reactive excited states. ( B ) Photoexcited Ru*(bpy) 3 2+ can act as an electron shuttle, interacting with sacrificial electron donors D (path i) or acceptors A (path ii) to yield either a strongly reducing or oxidizing catalyst toward organic substrates S. Ru*(bpy) 3 2+ can also directly transfer energy to an organic substrate to yield electronically excited species (path iii). bpy, 2,29-bipyridine; MLCT, metal-to-ligand charge transfer. Advances Over the past several years, there has been a resurgence of interest in synthetic photochemistry, based on the recognition that the transition metal chromophores that have been so productively exploited in the design of technologies for solar energy conversion can also convert visible light energy into useful chemical potential for synthetic purposes. Visible light enables productive photoreactions of compounds possessing weak bonds that are sensitive toward UV photodegradation. Furthermore, visible light photoreactions can be conducted by using essentially any source of white light, including sunlight, which obviates the need for specialized UV photoreactors. This feature has expanded the accessibility of photochemical reactions to a broader range of synthetic organic chemists. A variety of reaction types have now been shown to be amenable to visible light photocatalysis via photoinduced electron transfer to or from the transition metal chromophore, as well as energy-transfer processes. The predictable reactivity of the intermediates generated and the tolerance of the reaction conditions to a wide range of functional groups have enabled the application of these reactions to the synthesis of increasingly complex target molecules. Outlook This general strategy for the use of visible light in organic synthesis is already being adopted by a growing community of synthetic chemists. Much of the current research in this emerging area is geared toward the discovery of photochemical solutions for increasingly ambitious synthetic goals. Visible light photocatalysis is also attracting the attention of researchers in chemical biology, materials science, and drug discovery, who recognize that these reactions offer opportunities for innovation in areas beyond traditional organic synthesis. The long-term goals of this emerging area are to continue to improve efficiency and synthetic utility and to realize the long-standing goal of performing chemical synthesis using the sun.