A sequential construction of C-C, C-O, C═N, and C═O bonds from alkenes leading to the direct synthesis of isoxazolines in the presence of tert-butyl nitrite, quinoline, and the Sc(OTf) catalyst in DCE at 80 °C has been accomplished. An unprecedented three consecutive C-H functionalizations of two styrenes are involved in this isoxazoline synthesis. In this radical-mediated reaction, one-half of the aryl alkene is converted into an intermediate 2-nitroketone, which serves as a 1,3-dipolarophile and undergoes cycloaddition with the other half of the unreacted aromatic terminal alkene. The use of an alkyne in lieu of an alkene leads to the formation of isoxazole under identical reaction conditions.

Amino acid and peptide couplings are widely used in fields related to pharma and materials. Still, current peptide synthesis continues to rely on the use of expensive, water sensitive, and waste‐generating coupling reagents, which are often prepared in multi‐step sequences and used in excess. Herein is described a peptide coupling reaction design that relies mechanistically on sun‐light activation of a 4‐dimethylamino‐pyridine–alkyl halide charge‐transfer complex to generate a novel coupling reagent in situ. The resulting coupling method is rapid, does not require dry solvents or inert atmosphere, and is compatible with all the most common amino acids and protecting groups. Peptide couplings can be run on gram‐scale, without the use of special equipment. This method has a significantly reduced environmental and financial footprint compared to standard peptide coupling reactions. Experimental and computational studies support the proposed mechanism.

Intermolecular C-N bond formations via cross-dehydrogenative coupling (CDC) of aryl ethers and tetrazoles have been developed under a metal-free condition. In the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and aqueous TBHP, aryl ethers coupled efficiently with tetrazoles to afford hemiaminal ethers. This strategy showed high level of regioselectivity for substrates possessing multiple sp(3) C-H bonds adjacent to the ethereal oxygen.

C-3 alkylation of coumarins has been accomplished using cycloalkanes or alkylbenzenes in the presence of di-tert-butylperoxide (DTBP) and Fe(III) catalyst. Under metal free conditions and just by switching the oxidant from DTBP to TBHP, an exclusive C-4 cycloalkylation-C-3 peroxidation reaction takes place. During C-3 alkylation, the C-C bond formation occurs at the expense of an existing C-C bond, while the C-4 alkylation is associated with the formation of new C-C and C-O bonds.

Amino acid and peptide couplings are widely used in fields related to pharma and materials. Still, current peptide synthesis continues to rely on the use of expensive, water sensitive, and waste‐generating coupling reagents, which are often prepared in multi‐step sequences and used in excess. Herein is described a peptide coupling reaction design that relies mechanistically on sun‐light activation of a 4‐dimethylamino‐pyridine–alkyl halide charge‐transfer complex to generate a novel coupling reagent in situ. The resulting coupling method is rapid, does not require dry solvents or inert atmosphere, and is compatible with all the most common amino acids and protecting groups. Peptide couplings can be run on gram‐scale, without the use of special equipment. This method has a significantly reduced environmental and financial footprint compared to standard peptide coupling reactions. Experimental and computational studies support the proposed mechanism.

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Ruthenium(II) catalyzed oxidative C-H/O-H annulations have been demonstrated using two different directing arenes viz. 2-arylquinolinone and 2-arylbenzoxazinone with internal alkynes. Regiospecific annulations have been observed for both directing arenes via the assistance of weaker carbonyl oxygen in the presence of a stronger nitrogen-directing site. In this substrate-controlled convergent protocol the weaker directing group dictates the annulation path.

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