This article describes a highly effective catalytic asymmetric epoxidation method for olefins using potassium peroxomonosulfate (Oxone, Dupont) as oxidant and a fructose-derived ketone (1) as catalyst. High enantioselectivies have been obtained for trans-disubstituted and trisubstituted olefins which can bear functional groups such as tributylsilyl ether, acetal, chloride, and ester. The enantiomeric excesses for cis-olefins and terminal olefins are not high yet. The current epoxidation shows that the catalyst efficiency is enhanced dramatically upon raising the pH. Mechanistic studies show that the epoxidation mainly proceeds via a spiro transition state, which provides a model for predicting the stereochemical outcome of the reaction. The planar transition state is likely to be the main competing pathway. The extent of the involvement of the planar mode is subject to the steric effect of the alkyl groups on the olefins.

KRASG12C has emerged as a promising target in the treatment of solid tumors. Covalent inhibitors targeting the mutant cysteine-12 residue have been shown to disrupt signaling by this long-“undruggable” target; however clinically viable inhibitors have yet to be identified. Here, we report efforts to exploit a cryptic pocket (H95/Y96/Q99) we identified in KRASG12C to identify inhibitors suitable for clinical development. Structure-based design efforts leading to the identification of a novel quinazolinone scaffold are described, along with optimization efforts that overcame a configurational stability issue arising from restricted rotation about an axially chiral biaryl bond. Biopharmaceutical optimization of the resulting leads culminated in the identification of AMG 510, a highly potent, selective, and well-tolerated KRASG12C inhibitor currently in phase I clinical trials (NCT03600883).

Dioxiranes are remarkably versatile oxidizing agents that show encouraging potential for asymmetric synthesis, particularly asymmetric epoxidation of unfunctionalized olefins. This review outlines the recent development in this area. Discussions are focused on the structural requirements of the chiral ketone catalysts, how structural changes effect the reactivity and selectivity of the catalyst, reaction conditions, and transition states. 6 Carbocyclic Analogues 7 Exploring Other Oxidants 8 Conclusions

The efficacy of therapeutic antibodies that induce antibody-dependent cellular cytotoxicity can be improved by reduced fucosylation. Consequently, fucosylation is a critical product attribute of monoclonal antibodies produced as protein therapeutics. Small molecule fucosylation inhibitors have also shown promise as potential therapeutics in animal models of tumors, arthritis, and sickle cell disease. Potent small molecule metabolic inhibitors of cellular protein fucosylation, 6,6,6-trifluorofucose per-O-acetate and 6,6,6-trifluorofucose (fucostatin I), were identified that reduces the fucosylation of recombinantly expressed antibodies in cell culture in a concentration-dependent fashion enabling the controlled modulation of protein fucosylation levels. 6,6,6-Trifluorofucose binds at an allosteric site of GDP-mannose 4,6-dehydratase (GMD) as revealed for the first time by the X-ray cocrystal structure of a bound allosteric GMD inhibitor. 6,6,6-Trifluorofucose was found to be incorporated in place of fucose at low levels (<1%) in the glycans of recombinantly expressed antibodies. A fucose-1-phosphonate analog, fucostatin II, was designed that inhibits fucosylation with no incorporation into antibody glycans, allowing the production of afucosylated antibodies in which the incorporation of non-native sugar is completely absent-a key advantage in the production of therapeutic antibodies, especially biosimilar antibodies. Inhibitor structure-activity relationships, identification of cellular and inhibitor metabolites in inhibitor-treated cells, fucose competition studies, and the production of recombinant antibodies with varying levels of fucosylation are described.