Activated Iodosylbenzene Monomer as an Ozone Equivalent: Oxidative Cleavage of Carbon−Carbon Double Bonds in the Presence of Water

Metal-Free Chemoselective Oxidative Dehomologation or Direct Oxidation of Alcohols: Implication for Biomass Conversion

A transition metal-free, chemoselective reaction was performed using the sodium tert-butoxide-oxygen (NaO(t) Bu-O2 ) system, resulting in either oxidative dehomologation or direct oxidation of alcohols. In particular, the newly developed protocol may be used to predict the major product formed, which depends on alkyl chain length of the alcohols and reaction conditions. The rational mechanism of this transformation was also demonstrated by performing an (18) O isotopic labelling experiment. This protocol presents a straightforward method for biomass conversion of a lignin model compound to phenol and benzoic acid.

Carbon-Carbon Bond Cleavage Reaction: Synthesis of Multisubstituted Pyrazolo[1,5-a]pyrimidines

A new carbon-carbon bond cleavage reaction was developed for the efficient synthesis of multisubstituted pyrazolo[1,5-a]pyrimidines. This base induced reaction of 1,3,5-trisubstituted pentane-1,5-diones and substituted pyrazoles afforded good yields of the pyrazolo[1,5-a]pyrimidines.

Preparation, structure, and versatile reactivity of pseudocyclic benziodoxole triflate, new hypervalent iodine reagent

New, highly electrophilic hypervalent iodine reagent, triflate derivative of benziodoxole, was prepared and structurally characterized.

Direct approaches to nitriles via highly efficient nitrogenation strategy through C-H or C-C bond cleavage

Because of the importance of nitrogen-containing compounds in chemistry and biology, organic chemists have long focused on the development of novel methodologies for their synthesis. For example, nitrogen-containing compounds show up within functional materials, as top-selling drugs, and as bioactive molecules. To synthesize these compounds in a green and sustainable way, researchers have focused on the direct functionalization of hydrocarbons via C-H or C-C bond cleavage. Although researchers have made significant progress in the direct functionalization of simple hydrocarbons, direct C-N bond formation via C-H or C-C bond cleavage remains challenging, in part because of the unstable character of some N-nucleophiles under oxidative conditions. The nitriles are versatile building blocks and precursors in organic synthesis. Recently, chemists have achieved the direct C-H cyanation with toxic cyanide salts in the presence of stoichiometric metal oxidants. In this Account, we describe recent progress made by our group in nitrile synthesis. C-H or C-C bond cleavage is a key process in our strategy, and azides or DMF serve as the nitrogen source. In these reactions, we successfully realized direct nitrile synthesis using a variety of hydrocarbon groups as nitrile precursors, including methyl, alkenyl, and alkynyl groups. We could carry out C(sp(3))-H functionalization on benzylic, allylic, and propargylic C-H bonds to produce diverse valuable synthetic nitriles. Mild oxidation of C═C double-bonds and C≡C triple-bonds also produced nitriles. The incorporation of nitrogen within the carbon skeleton typically involved the participation of azide reagents. Although some mechanistic details remain unclear, studies of these nitrogenation reactions implicate the involvement of a cation or radical intermediate, and an oxidative rearrangement of azide intermediate produced the nitrile. We also explored environmentally friendly oxidants, such as molecular oxygen, to make our synthetic strategy more attractive. Our direct nitrile synthesis methodologies have potential applications in the synthesis of biologically active molecules and drug candidates.

PIFA-mediated esterification reaction of alkynes with alcohols via oxidative cleavage of carbon triple bonds

A metal-free esterification of alkynes via C≡C triple bond cleavage has been developed. In the presence of phenyliodine bis(trifluoroacetate), a diverse range of alkyne and alcohol substrates undergoes triple bond cleavage to produce carboxylic ester motifs in moderate to good yields. The transformation is proposed to proceed via hydroxyethanones and ethanediones as intermediates on the basis of mechanistic studies and exhibits a broad substrate scope and good functional group tolerance.

Copper(ii)-catalyzed cleavage of carbon–carbon triple bond to synthesize 1,2,3-triesterindolizines

An efficient Cu(ii)-catalyzed carbon–carbon triple bond cleavage protocol for the synthesis of 1,2,3-triesterindolizines via the reaction of pyridines with butynedioates has been developed.

An amphiphilic, catalytically active, vitamin B12 derivative

The reaction of vitamin B₁₂ with DMF-DMA and MeOH as a nucleophile affords cobalester, the first amphiphilic cobalamin derivative which is able to catalyze C–C bond forming reactions.

meta-Chloroperbenzoic acid (mCPBA): a versatile reagent in organic synthesis

This review aims to collect and discuss the synthetic applications of meta-chloroperbenzoic acid (mCPBA) over the past few decades.

Tetraethylammonium iodide catalyzed synthesis of diaryl ketones via the merger of cleavage of C–C double bonds and recombination of aromatic groups

An efficient method for synthesizing diaryl ketones via merging oxidative cleavage of C–C double bonds and recombination of aromatic groups is developed with Et₄NI (2.5 mol%) as the catalyst and NaIO₄ as the oxidant.

Cleavage of carbon-carbon triple bond: direct transformation of alkynes to nitriles

A new cleavage reaction of carbon-carbon triple bonds proceeds efficiently with NIS and TMSN3, giving the corresponding nitriles in moderate to good yields.

Expanding the regioselective enzymatic repertoire: oxidative mono-cleavage of dialkenes catalyzed by Trametes hirsuta

The first report of a biocatalytic regioselective oxidative mono-cleavage of dialkenes was successfully achieved employing a cell-free enzyme preparation from Trametes hirsuta at the expense of molecular oxygen. Selected reactions were performed on a preparative scale affording high to excellent conversions and chemoselectivities.