PyrAtes: Modular Organic Salts with Large Stokes Shifts for Fluo-rescence Microscopy.

The deployment of small-molecule fluorescent agents plays an ever-growing role in medicine and drug development. Herein, we complement the portfolio of powerful fluorophores, reporting the serendipitous discovery and development of a novel class with an imidazo[1,2-a]pyridinium triflate core, which we term PyrAtes. These fluorophores are synthesized in a single step from readily available materials (>60 examples) and display Stokes shifts as large as 240 nm, while also reaching NIR-I emissions at λmax as long as 720 nm. Computational studies allow the development of a platform for the prediction of λmax and λEm. Furthermore, we demonstrate the compatibility of these novel fluorophores with live cell imaging in HEK293 cells, suggesting PyrAtes as potent intracellular markers.

Regio- and Chemoselective Double Allylic Substitution of Alkenyl vic-Diols.

Double allylic substitution is an attractive approach to building molecular complexity from simple starting materials by creating two new bonds in one pot. However, this type of reaction has been doomed by chemoselectivity and regioselectivity issues. In this letter, we describe a new approach to introduce a-la-carte two new C-C, C-N, C-O, or C-S bonds in a chemo- and regioselective fashion. The reaction relies on sequential dual catalysis with a Lewis acid and palladium. The scope is remarkably broad, and the reaction can be diastereoselective by using secondary alcohols as the first nucleophile.