Stereoselective synthesis of allele-specific BET inhibitors

Copper(I)-catalyzed asymmetric alkylation of α-imino-esters

Asymmetric alkylation of enolates is one of the most direct and important reactions to prepare α-chiral carbonyl compounds. Except for the classical methods that rely on the use of chiral auxiliaries, asymmetric catalysis emerged as a powerful tool, especially asymmetric phase-transfer catalysis. However, in the field of transition metal catalysis, only limited success with asymmetric alkylation of enolates was achieved. Hereby, we disclose a copper(I)-catalyzed asymmetric alkylation of α-imino-esters with various alkyl halides, including allyl bromides, propargyl bromide, benzyl bromides, α-bromo carbonyl compounds, and alkyl iodides. Both linear and cyclic α-imino-esters serve as competent pronucleophiles in the alkylation, which affords α-amino acid derivatives bearing either a trisubstituted or a tetrasubstituted stereogenic carbon center in high to excellent enantioselectivity. Control experiments indicate that the α-imino-ester is activated by a chiral copper(I)-phosphine complex through coordination, thus enabling facile deprotonation to provide a stabilized copper(I)-enolate in the presence of a mild base. Finally, the mildly basic nature allows the asymmetric alkylation of chiral dipeptides with excellent both chemo- and enantioselectivities.

Frontiers in Medicinal Chemistry 2022 Goes Virtual

The Frontiers in Medicinal Chemistry (FiMC) meeting, which represents the largest international medicinal chemistry conference in Germany, took place from March 14^th to 16^th 2022 in a fully virtual format. Organized by the Division of Medicinal Chemistry of the German Chemical Society (GDCh) together with the Division of Pharmaceutical & Medicinal Chemistry of the German Pharmaceutical Society (DPhG) and a "local" organization committee from the University of Freiburg headed by Manfred Jung, the meeting brought together 271 participants from around 20 countries. The program included 33 lectures by leading scientists from industry and academia as well as early career investigators. 67 posters were presented in two poster sessions and with over 20.000 poster abstract downloads. The general organization and the time-shift function were very much appreciated as demonstrated by almost 600 on-demand contents retrieved. The online format fitted perfectly to bring together medicinal chemists from academia and industry across the globe.

Development of BromoTag: A "Bump-and-Hole"-PROTAC System to Induce Potent, Rapid, and Selective Degradation of Tagged Target Proteins

Small-molecule-induced protein depletion technologies, also called inducible degrons, allow degradation of genetically engineered target proteins within cells and animals. Here, we design and develop the BromoTag, a new inducible degron system comprising a Brd4 bromodomain L387A variant as a degron tag that allows direct recruitment by heterobifunctional bumped proteolysis targeting chimeras (PROTACs) to hijack the VHL E3 ligase. We describe extensive optimization and structure-activity relationships of our bump-and-hole-PROTACs using a CRISPR knock-in cell line expressing model target BromoTag-Brd2 at endogenous levels. Collectively, our cellular and mechanistic data qualifies bumped PROTAC AGB1 as a potent, fast, and selective degrader of BromoTagged proteins, with a favorable pharmacokinetic profile in mice. The BromoTag adds to the arsenal of chemical genetic degradation tools allowing us to manipulate protein levels to interrogate the biological function and therapeutic potential in cells and in vivo.