Rational Modification of a Cross-Linker for Improved Flexible Protein Structure Modeling.

Chemical cross-linking/mass spectrometry (XL-MS) has emerged as a complementary tool for mapping interaction sites within protein networks as well as gaining moderate-resolution native structural insight with minimal interference. XL-MS technology mostly relies on chemoselective reactions (cross-linking) between protein residues and a linker. DSSO represents a versatile cross-linker for protein structure investigation and in-cell XL-MS.

Stereodivergent 1,3-difunctionalization of alkenes by charge relocation.

Alkenes are indispensable feedstocks in chemistry. Functionalization at both carbons of the alkene-1,2-difunctionalization-is part of chemistry curricula worldwide. Although difunctionalization at distal positions has been reported, it typically relies on designer substrates featuring directing groups and/or stabilizing features, all of which determine the ultimate site of bond formation.

Isothiouronium-Mediated Conversion of Carboxylic Acids to Cyanomethyl Thioesters.

We report the development of an isothiouronium salt as a reagent for the operationally simple synthesis of cyanomethyl thioesters with high functional group tolerance and avoiding the use of thiols. Additionally, we show that the products can be engaged in amide synthesis in either a two-step or one-pot fashion.

Synthesis, Structure, and Reactivity of Binaphthyl Supported Dihydro[1,6]diazecines.

A short approach to chiral diaza-olefines from protected 2,2'-diamino-1,1'-binaphthyl is presented. - and -olefines can be selectively obtained by twofold -allylation followed by RCM or by bridging a 2,2'-diamino-1,1'-binaphthyl precursor with -1,4-dibromo-2-butene. Deprotection afforded - and -dihydro[1,6]diazecines in 58 and 64% overall yield.

On the formation of seven-membered rings by arene-ynamide cyclization.

Abstract: A Brønsted acid-catalyzed selective arene-ynamide cyclization is described. This reaction proceeds via a keteniminium intermediate and enables the preparation of seven-membered ring enamide products. Mechanistic studies uncover an unusual product inhibition behavior.

Chemoselective Activation of Diethyl Phosphonates: Modular Synthesis of Biologically Relevant Phosphonylated Scaffolds.

Phosphonates have garnered considerable attention for years owing to both their singular biological properties and their synthetic potential. State-of-the-art methods for the preparation of mixed phosphonates, phosphonamidates, phosphonothioates, and phosphinates rely on harsh and poorly selective reaction conditions. We report herein a mild method for the modular preparation of phosphonylated derivatives, several of which exhibit interesting biological activities, that is based on chemoselective activation with triflic anhydride.