1094615-15-2Relevant academic research and scientific papers
Catalyst-Free Formal Thioboration to Synthesize Borylated Benzothiophenes and Dihydrothiophenes
Faizi, Darius J.,Davis, Ashlee J.,Meany, Fiach B.,Blum, Suzanne A.
, p. 14286 - 14290 (2016/11/11)
The first ring-forming thioboration reaction of C?C π bonds is reported. This catalyst-free method proceeds in the presence of a commercially available external electrophilic boron source (B-chlorocatecholborane) in good to high yields. The method is scalable and tolerates a variety of functional groups that are intolerant of other major borylation methods. The resulting borylated benzothiophenes participate in a variety of in situ derivatization reactions, showcasing that these borylated intermediates do not need to be isolated prior to downstream functionalization. This methodology has been extended to the synthesis of borylated dihydrothiophenes. Mechanistic experiments suggest that the operative mechanistic pathway is through boron-induced activation of the alkyne followed by electrophilic cyclization, as opposed to S?B σ bond formation, providing a mechanistically distinct pathway to the thioboration of C?C π bonds.
Competition studies in alkyne electrophilic cyclization reactions
Mehta, Saurabh,Waldo, Jesse P.,Larock, Richard C.
supporting information; experimental part, p. 1141 - 1147 (2009/07/11)
The relative reactivity of various functional groups toward alkyne electrophilic cyclization reactions has been studied. The required diarylalkynes have been prepared by consecutive Sonogashira reactions of appropriately substituted aryl halides and competitive cyclizations have been performed using I2, ICl, NBS and PhSeCl as electrophiles. The results indicate that the nucleophilicity of the competing functional groups, polarization of the alkyne triple bond, and the cationic nature of the intermediate are the most important factors in determining the outcome of these reactions.
