Sujoy Rana

Efficient and Stereoselective Nitration of Mono- and Disubstituted Olefins with AgNO2 and TEMPO

Nitroolefin is a common and versatile reagent. Its synthesis from olefin is generally limited by the formation of mixture of cis and trans compounds. Here we report that silver nitrite (AgNO2) along with TEMPO can promote the regio- and stereoselective nitration of a broad range of olefins. This work discloses a new and efficient approach wherein starting from olefin, nitroalkane radical formation and subsequent transformations lead to the desired nitroolefin in a stereoselective manner.

A general and efficient aldehyde decarbonylation reaction by using a palladium catalyst

A facile decarbonylation reaction of aldehydes has been developed by employing Pd(OAc)(2). A wide variety of substrates are decarbonylated, without using any exogenous ligand for palladium as well as CO-scavenger.

ipso-Nitration of arylboronic acids with bismuth nitrate and perdisulfate.

An efficient and one pot synthetic method of ipso-nitration of arylboronic acids has been developed. The high efficiency, general applicability, and broader substrate scope including heterocycles and functional groups make this method advantageous. Due to its simplicity, we expect to find application of this method in synthesis.

Iron-Catalyzed Regioselective Direct Arylation at the C-3 Position of N-Alkyl-2-pyridone

A number of pharmaceutical compounds possess an arylated 2-pyridone moiety. The existing reports using expensive starting materials and/or superstoichiometric metal salts have prompted us to explore a possible user-friendly method for their synthesis. In this report, we demonstrate an easy-to-handle reaction condition with an iron catalyst for the exclusive generation of C-3-arylated pyridone via C-H functionalization.

Mechanistic elucidation of C-H oxidation by electron rich non-heme iron(IV)-oxo at room temperature.

Non-heme iron(IV)-oxo species form iron(III) intermediates during hydrogen atom abstraction (HAA) from the C-H bond. While synthesizing a room temperature stable, electron rich, non-heme iron(IV)-oxo compound, we obtained iron(III)-hydroxide, iron(III)-alkoxide and hydroxylated-substrate-bound iron(II) as the detectable intermediates. The present study revealed that a radical rebound pathway was operative for benzylic C-H oxidation of ethylbenzene and cumene. A dissociative pathway for cyclohexane oxidation was established based on UV-vis and radical trap experiments. Interestingly, experimental evidence including O-18 labeling and mechanistic study suggested an electron transfer mechanism to be operative during C-H oxidation of alcohols (e.g. benzyl alcohol and cyclobutanol). The present report, therefore, unveils non-heme iron(IV)-oxo promoted substrate-dependent C-H oxidation pathways which are of synthetic as well as biological significance.

Decarbonylative halogenation by a vanadium complex.

Metal-catalyzed halogenation of the C-H bond and decarbonylation of aldehyde are conventionally done in nature. However, metal-mediated decarbonylative halogenation is unknown. We have developed the first metal-mediated decarbonylative halogenation reaction starting from the divanadium oxoperoxo complex K3V(5+)2(O2(2-))4(O(2-))2(μ-OH) (1). A concerted decarbonylative halogenation reaction was proposed based on experimental observations.

Manganese-salen catalyzed oxidative benzylic chlorination

Metalloporphyrins are well-known to serve as the model for mimicking reactivities exhibited by cytochrome P450 hydroxylase. Recent developments on selective C–H halogenation using Mn-porphyrins provided the way for understanding the reactivity as well as mechanism of different halogenase enzymes. In this report, we demonstrated a method for benzylic C–H chlorination using easily prepared Mn(salen) complex as the catalyst, which shows a complementary reactivity of Mn-porphyrins. Here, NaOCl has been used as a chlorinating source as well as the oxidant. Efforts towards understanding the mechanism suggested the formation of the high-valent Mn(V)=O species which is believed to be the key intermediate to conduct this transformation.Graphical abstractSYNOPSIS Mn(salen)-catalyzed selective benzylic chlorination protocol has been developed using aqueous NaOCl solution. Reactions proceeded efficiently at room temperature and displayed good functional group tolerance. The mechanistic investigation demonstrated that

Synthesis of Bis(heteroaryl) Ketones by Removal of Benzylic CHR and CO Groups

\hbox {Mn}(\hbox {V}){=}\hbox {O}