765906-56-7Relevant academic research and scientific papers
Br?nsted acid-promoted cyclizations of siloxy alkynes with unactivated arenes, alkenes, and alkynes
Zhang, Liming,Sun, Jianwei,Kozmin, Sergey A.
, p. 11371 - 11380 (2006)
In this article, we describe the development of a general concept for the development of new carbon-carbon bond-forming processes, which is based on Br?nsted acid-mediated activation of a siloxy alkyne, followed by efficient interception of the resulting highly reactive ketenium ion by unactivated arenes, alkenes or alkynes. We found that trifluoromethane sulfonimide (HNTf2) proved to be a superior promoter of these reactions compared to a range of other Br?nsted acids. This finding could be attributed to a high acidity of HNTf2 in aprotic organic solvents combined with a low nucleophilicity of the NTf2- anion. Depending on the nature of the nucleophile, the carbocyclizations proceeded either via 6-endo-dig or 5-endo-dig manifolds. In the case of 1-siloxy-1,5-diynes, the cyclizations occurred with a concomitant halide abstraction or arylation.
