Carboxy to methyl reduction is an important transformation in organic synthesis, yet existing methodologies often require multi-step procedures or use hazardous metal hydrides. Herein, a metal-free catalytic system is reported for the one-step reduction of esters, carboxylic acids, and carbamates to a methyl group, in the presence of catalytic amounts of boronic acids. By using ammonia borane as a hydrogen donor, a wide range of products bearing different functional groups can be obtained in high yields under relatively mild conditions. Mechanistic studies and control experiments elucidate the complexity of the mechanism and provide an explanation for the observed selectivity.

We report the formation of NHC complexes of mono- and bis-hydrazino boranes with N–N–B and N–N–B–N–N chains via the reaction of NHC-boranes with electrophilic azo reagents. The influence of steric hindrance on the carbene and on the azo reagent has been shown to be crucial for the reactivity. The hydroboration of dissymmetric azo reagents is regioselective only when the latter is sufficiently electronically twisted. Bis-hydrazino borane complexes with two different hydrazine arms could be obtained via sequential addition.

A phosphine-catalyzed (3+2) annulation of Morita–Baylis–Hillman carbonates with pyrazolinone-derived ketimines has been achieved to give various spirodihydropyrrole/dihydropyrazolones in moderate to high yields with good diastereoselectivities. The protocol proved to be efficient with diverse MBH carbonates and ketimines. Both scale-up reaction and further transformation of the product were successfully. In addition, up to 98% ee of chiral product was obtained with the use of chiral bifunctional phosphine.

The synthesis and optical properties of wheel-shaped nanographdiynes that has lost some butadiyne spokes were reported. These defective wheel-shaped nanographdiynes possess butadiyne-bridged metacyclophanes with para-bis(phenylbutadiynyl)-benzene units as the axis. The optimized geometries of the defective wheel-shaped nanographdiynes along with their vibrational spectra, HOMO and LUMO orbitals were calculated at B3LYP/6-311G(d,p) level. HOMO and LUMO orbitals are delocalized mainly over the para-bis(phenylbutadiynyl)-benzene axis, with weak contribution from the attached ethynyl units. The π-conjugation extension and quantity increase of the para axis influenced the optical properties of these graphdiyne substructures, leading to the change of bandgap from 2.88 eV to 2.56 eV as reflected by optical spectroscopy. The defective wheel-shaped nanographdiynes lost the characteristic intensive sharp absorption peak at low energy region, which indicated that the fusion of adjacent dehydrobenzo [18] annulenes are crucial for the bulk properties of graphdiyne.

Synthetic methodologies based on cycle expansion reactions have proven to be highly effective in delivering valuable medium-sized cycles and macrocycles. A primary method of ring expansion relies on intramolecular transamidation reactions. These reactions typically employ N-aminoalkyl and N-aminoacyl derivatives of lactams and their analogues as starting materials, yielding a diverse spectrum of unique nitrogen-containing heterocycles. This Review aims to provide a comprehensive analysis of the research outcomes related to intramolecular transamidation reactions that lead to cycle expansion. This will offer the reader a perspective on the potential applications of such reactions in generating novel and intriguing types of heterocyclic systems.

N-Heterocyclic carbene (NHC) catalyzed radical-radical reactions have been proven to be powerful strategies for assembling ketyl-containing compounds via single electron transfer (SET) pathway under either thermal conditions or photoredox conditions. In this context, acylation of alkenes via radical relay under NHC-organocatalysis has also opened a new window for the difunctionalization of alkenes to construct valuable molecules in organic synthesis. In this review, the advances and progress of the acylation of alkenes via NHC-organocatalysis were summarized according to different ways of generation of the key NHC-bound ketyl-type radicals. Furthermore, reaction scopes, limitations and mechanisms were discussed based on reaction types and catalytic systems. Conclusions and perspectives were also put forward at the end.

Studies into the ring-closing enyne metathesis of a series of nine sulfone containing enynes is described.  The readily accessible sulfone substrates were shown to undergo cyclisation to form 3-subsituted 2,5-dihydrothiophene 1,1-dioxides (sulfolenes) and one 3,6-dihydro-2H-thiopyran 1,1-dioxide.  The success of this process depended on the substrate’s substitution pattern.  Moderate to good yields of the products were obtained when the ene component was monosubstituted and it was found that the reactions proceeded most efficiently using the 2nd generation Grubbs catalysts, at elevated temperatures.

An original synthetic strategy is presented for the preparation of the sensitive 3-amino-4-hydroxypyrrolidinone-4-acetic acid residue which is present in the structures of the microsclerodermin natural product family. The approach relies on the use of a linear γ-amino acid surrogate derived from asparagine bearing a β-dithiolanyl group. A protected dipeptide model system is used to demonstrate that selective removal of the dithioketal protection followed by cyclization gives the target structure in single diastereoisomer form and with little or no dehydration.

The Front Cover shows images of buds and blossomed waterlilies. As the sun favours the blossoming of the waterlilies, a molecular recognition event triggers a conformational change of the isopropoxy-prism[6]arene from a closed to open structure. Cover design by Rocco Del Regno, Carmine Gaeta and Silvano Geremia. More information can be found in the Research Article by R. Del Regno, S. Geremia, C. Gaeta et al.

The 5-ammonium-4,4-dimethylvaleryl (Amv) group was generated by conversion of acryloyl group through decatungstatecatalyzed addition of C(sp3)–H bond of i-BuNH2·HCl under the irradiation of UV light (365 nm or 405 nm). Treatment of Amvprotected alcohols and anilines with aqueous Na2CO3 promoted the efficient deprotection of Amv. This is a unique method for the efficient removal of acryloyl groups from phenols, alcohols, and anilines. The selective removal of acryloyl groups through Amv in the presence of another acetyl or benzoyl group was demonstrated. The basetriggered intramolecular cyclization of Amv was monitored by the release of a fluorescent molecule, and it was found that cyclization by Na2CO3 was very rapid (within 1 min) and that some weak bases such as 2,6-lutidine are sufficient to promote cyclization.