Massimo Christian D'ALterio

We present a comprehensive mechanistic investigation of the well‐defined precatalyst [Pd(IMes ^Me )(cin)Cl], which has exhibited high catalytic efficiency in the Miyaura borylation of various aryl chlorides. Despite its proven catalytic performance, key aspects of the mechanism, particularly the transmetalation step, remained elusive. In this study, we addressed these mechanistic aspects through detailed density functional theory (DFT) calculations. Our results elucidate the role of the second equivalent of base, pinpointing its specific involvement within the catalytic cycle. Furthermore, we unraveled the activation pathway of bis(pinacolato)diboron (B ₂ Pin ₂ ), determining whether base‐mediated cleavage occurs independently or requires direct coordination to the palladium center. The mechanism reveals a surprising concerted fusion of the oxidative addition and transmetalation steps, paving the way not only for a new avenue in the Miyaura reaction, but potentially for other cross‐coupling processes. This synergy may prompt a re‐evaluation of previous studies, suggesting that similar pathways could enable milder reaction conditions.

Selective ring-opening polymerization (ROP) of chiral lactones enables access to biodegradable polyesters with precisely controlled microstructures. Here, combined DFT modeling and experimental validation elucidate how fine-tuning of enantiopure SalBinam aluminum catalysts (through introduction of bromine atoms and tert-butyl groups, respectively, in ortho- and para-positions) modulates regio- and stereocontrol in the ROP of methyl glycolide (MeG) and lactide (LA). Computations reveal that regioselectivity in MeG polymerization arises mainly from steric repulsion, with a small contribution from weak stabilizing C-H···Br interactions that favor ring-opening at the glycolic site, consistent with the experimentally enhanced regioselectivity for (R)-MeG. In contrast, the same steric congestion at the ligand’s ortho positions destabilizes the key transition states in rac-LA polymerization, reducing the calculated stereoselectivity. Experiments confirm the predicted loss of stereocontrol, yielding nearly atactic PLA under standard conditions. Extension of the computational framework to rac-MeG polymerization promoted by racemic catalyst identified a low-barrier, stepwise polymer chain exchange pathway that rationalizes the experimentally observed syndiotacticity of poly(lactic-co-glycolic acid).

An earth-abundant Fe­(II)-based catalyst was employed for efficient and sustainable ring-opening polymerization of naturally occurring ε- and δ-lactones. High turnover frequencies (TOFs) and excellent control over the polymerization of δ-substituted δ-lactones demonstrate the catalyst’s ability to process monomers traditionally considered challenging or poorly polymerizable. Density Functional Theory (DFT) calculations suggest the formation of dinuclear iron species and underscore the mechanistic complexity of the system, including a monomer-dependent variation in the rate-determining step.

Enantiopure isotactic poly(cyclohexene carbonate) (PCHC) has been synthesized with chiral Zn‐β‐diiminate catalyst. PCHC crystallizes both as enantiopure polymer ( R )‐PCHC and ( S )‐PCHC and upon stereocomplexation of the two enantiomers. We report the crystal structures of the enantiopure polymer and of the stereocomplex ( R / S )‐PCHC and explain their crystallization based on the establishment of multiple attractive H‐‐‐O═C interactions between oxygen atoms of carbonyl groups and the hydrogen atoms of the cyclohexyl rings and C═O‐‐‐C═O intimate dipole interactions between carbonyl groups of chains of opposite chirality in the stereocomplex. The crystal structure of the enantiopure polymer is characterized by chains in 2/1 helical conformation packed in the orthorhombic unit cell with axes a  = 11.55 Å , b  = 9.42 Å, and c  = 7.36 Å, according to the space group P 2 ₁ 2 ₁ 2 ₁ , with steric interdigitation between chains of similar chirality favored by multiple attractive H‐‐‐O═C interactions. The stereocomplex crystallizes in an orthorhombic unit cell with axes a = 10.40 Å, b  = 8.41 Å, and c = 7.36 Å, according to the space group Pbc 2 ₁ , driven by establishment of additional C═O‐‐‐C═O dipole interactions between carbonyl groups of chains of opposite chirality, besides of the multiple attractive H‐‐‐O═C interactions.

Enantiopure isotactic poly(cyclohexene carbonate) (PCHC) has been synthesized with chiral Zn‐β‐diiminate catalyst. PCHC crystallizes both as enantiopure polymer ( R )‐PCHC and ( S )‐PCHC and upon stereocomplexation of the two enantiomers. We report the crystal structures of the enantiopure polymer and of the stereocomplex ( R / S )‐PCHC and explain their crystallization based on the establishment of multiple attractive H‐‐‐O═C interactions between oxygen atoms of carbonyl groups and the hydrogen atoms of the cyclohexyl rings and C═O‐‐‐C═O intimate dipole interactions between carbonyl groups of chains of opposite chirality in the stereocomplex. The crystal structure of the enantiopure polymer is characterized by chains in 2/1 helical conformation packed in the orthorhombic unit cell with axes a  = 11.55 Å , b  = 9.42 Å, and c  = 7.36 Å, according to the space group P 2 ₁ 2 ₁ 2 ₁ , with steric interdigitation between chains of similar chirality favored by multiple attractive H‐‐‐O═C interactions. The stereocomplex crystallizes in an orthorhombic unit cell with axes a = 10.40 Å, b  = 8.41 Å, and c = 7.36 Å, according to the space group Pbc 2 ₁ , driven by establishment of additional C═O‐‐‐C═O dipole interactions between carbonyl groups of chains of opposite chirality, besides of the multiple attractive H‐‐‐O═C interactions.

A regio- and stereoselective synthesis for the effecient formation of 5-(trichloromethyl)-isoxazolines under mild, metal-free conditions has been developed based on the reaction of CCl₃-enones with aromatic hydroxamoyl chlorides.

The factors contributing to the enantioselective ring opening copolymerization of CO₂ and meso-epoxide have been unveiled by DFT calculations combined with activation strain model and noncovalent interaction analysis.

Switching the preference in stereocontrolled rac -LA ROP.