1449574-69-9Relevant academic research and scientific papers
Br?nsted Acid-Catalyzed Enantioselective Cycloisomerization of Arylalkynes
Abadie, Baptiste,Berlande, Murielle,Dhara, Kalyan,Gicquiaud, Julien,Hermange, Philippe,Sotiropoulos, Jean-Marc,Toullec, Patrick Y.
, p. 16266 - 16271 (2020)
The first example of an enantioselective carbocyclization of an alkyne-containing substrate catalyzed by chiral Br?nsted acids was achieved. The use of the 2-hydroxynaphthyl substituent on the alkyne as a directing group constituted the key parameter enabling both efficient regioselective protonation of the carbon–carbon triple bond and chiral induction. The key cationic intermediate could be depicted either as a cationic vinylidene ortho-quinone methide or a stabilized vinyl cation. Atropoisomeric phenanthrenes derivatives were produced in high yields and good enantioselectivities under mild, metal-free reaction conditions in the presence of chiral N-triflylphosphoramide catalysts. The carbenic nature of the cationic intermediate was also exploited to describe an example of alkyne/alkane cycloisomerization.
A flexible metal-catalyzed synthesis of highly substituted aryl phenanthrenyl selenides
Lim, Wontaeck,Rhee, Young Ho
supporting information, p. 460 - 464 (2013/02/25)
An efficient method for the preparation of diaryl selenides, which are important in biology and materials science, is described. Specifically, the development of highly substituted phenanthrenyl phenyl selenides 4 and 6 by metal-catalyzed cyclization of o-phenylarylalkynes species 1 was successfully performed. The selectivity for 9- and 10-selenyl phenanthrenes was perfectly controlled by indium(III) and gold(I) catalysts, and the reactions proceed through different pathways. For the In(OTf)3 catalyst system, 6-endo cyclization of alkyne 3 gives product 4 in which the selenium group is retained. In contrast, for the AuCl(IPr)/AgSbF6 catalyst system, transformation of metal-alkyne complex 2 into vinylidene-gold intermediate 5 gives product 6 in which the selenium group is migrated. Various substrates, even electronically poor substrates, can be converted into phenanthrenes with high selectivity in high yield under very mild conditions. Highly substituted 9- and 10-selenylphenanthrenes are easily prepared from the corresponding selenium-containing (o-phenylaryl)alkynes. The selectivity is perfectly controlled by indium(III) and gold(I) catalysts. Various substrates can be converted into phenanthrene derivatives with high selectivity and in good yield under very mild conditions. Copyright
