Photochemical Functionalization of Heterocycles with EBX Reagents: C−H Alkynylation versus Deconstructive Ring Cleavage**
作者:Errika Voutyritsa、Marion Garreau、Maroula G. Kokotou、Ierasia Triandafillidi、Jérôme Waser、Christoforos G. Kokotos
DOI:10.1002/chem.202002868
日期:2020.11.11
The development of novel methodologies for the functionalization of saturated heterocycles is highly desirable. Herein, we report a cheap and efficient photochemical method for the C−H functionalization of saturated O‐heterocycles, as well as the deconstructive ring‐cleavage of S‐heterocycles, employing hypervalent iodine alkynylation reagents (ethynylbenziodoxolones, EBX). This photochemical alkynylation
The synthesis of a series of 5‐(alkynyl) dibenzothiophenium triflates, prepared from dibenzo[b,d]thiophene 5‐oxide and the corresponding trimethylsilyl‐substituted alkynes is reported. Their structures were determined by X‐ray crystallography, and their reactivities as electrophilic alkynylation reagents evaluated. Their broad substrate scope and functional‐group tolerance illustrate their potential
A Highly Chemoselective and Practical Alkynylation of Thiols
作者:Reto Frei、Jérôme Waser
DOI:10.1021/ja4044196
日期:2013.7.3
A thiol-alkynylation procedure utilizing the hypervalent iodine alkyne transfer reagent TIPS-ethynyl-benziodoxolone has been developed. This scalable reaction proceeds in five minutes at room temperature in an open flask using commercially available reagents. The scope of the reaction is broad, with a variety of phenolic, benzylic, heterocyclic, and aliphatic thiols undergoing alkynylation in excellent yield. The method is highly chemoselective as a vast array of functional groups are tolerated. The utility of the thiol-alkynylation in postsynthetic elaboration has been demonstrated through the facile installment of a fluorophore tag on a cysteine-containing peptide.