Chiral C2- and C1-symmetric BINOL-derived bis(phosphoric acid) catalysts facilitated the enantioselective aza-Friedel–Crafts reaction of 2-methoxyfuran with α-ketimino esters.

A highly chemoselective transesterification of methyl (meth)acrylates catalyzed by sterically demanding 2,6-di-tertbutyl-4-methylphenol (BHT)-derived NaOAr or Mg(OAr)2 was developed. The desired transesterification proceeded without undesired Michael additions under mild reaction conditions at 25 °C, and various primary and secondary alcohols, diols, triol, and tetraol on a scale of up to 10 mmol could provide the corresponding functionalized acrylates in high yields. Transition states were proposed based on monomeric and dimeric active species, and computational DFT calculations strongly supported the high chemoselectivity to minimize undesired Michael additions.

A metal-free [Me4N]+[OCO2Me]− catalyst is effective for the chemoselective, scalable, and reusable transesterification of chelating substrates in common organic solvents.

A hydrogen bonding network in chiral Brønsted acid catalysts is important for the construction of a chiral cavity and the enhancement of catalytic activity. In this regard, we developed a highly enantioselective aza-Friedel–Crafts reaction of indoles and pyrroles with acyclic α-ketimino esters in the presence of a chiral C 1-symmetric BINOL-derived bis­(phosphoric acid) catalyst. The desired alkylation products with chiral quaternary carbon centers were obtained in high yields with high enantioselectivities on up to a 1.2-g scale with 0.2 mol % catalyst loading. Interestingly, the absolute configurations of the products from indoles and pyrroles were opposite even with the use of the same chiral catalyst. Moreover, preliminary mechanistic considerations disclosed that a unique hydrogen bonding network with or without π–π interactions among the catalyst and substrates might partially play a pivotal role.

Covalent inhibitors of enzymes are increasingly appreciated as pharmaceutical seeds, yet discovering non-cysteinetargeting inhibitors remains challenging. Herein, we report an intriguing experience during our activity-based proteomic screening of 1601 reactive small molecules, in which we monitored the ability of library molecules to compete with a cysteine-reactive iodoacetamide probe. One epoxide molecule, F8, exhibited unexpected enhancement of the probe reactivity for glyceraldehyde-3phosphate dehydrogenase (GAPDH), a rate-limiting glycolysis enzyme. In-depth mechanistic analysis suggests that F8 forms a covalent adduct with an aspartic acid in the active site to displace NAD + , a cofactor of the enzyme, with concomitant enhancement of the probe reaction with the catalytic cysteine. The mechanistic underpinning permitted the identification of an optimized aspartate-reactive GAPDH inhibitor. Our findings exemplify that activity-based proteomic screening with a cysteine-reactive probe can be used for discovering covalent inhibitors that react with non-cysteine residues.