In 2018,Kita, Yuji; Yata, Tetsuji; Nishimoto, Yoshihiro; Chiba, Kouji; Yasuda, Makoto published 《Selective oxymetalation of terminal alkynes via 6-endo cyclization: mechanistic investigation and application to the efficient synthesis of 4-substituted isocoumarins》.Chemical Science published the findings.Synthetic Route of Br3In The information in the text is summarized as follows:
Herein, a novel cyclic oxymetalation of 2-alkynylbenzoate with indium or gallium salts that proceeds with an unusual regioselectivity to give isocoumarins bearing a carbon-metal bond at the 4-position was reported. Indium and gallium salts showed high performance in the selective 6-endo cyclization of terminal alkynes while boron or other metals such as Al, Au, and Ag caused 5-exo cyclization or decomposition of terminal alkynes, resp. The metalated isocoumarin and its reaction intermediate were unambiguously identified by X-ray crystallog. anal. The theor. calculation of potential energy profiles showed that oxyindation could proceed via 6-endo cyclization under thermodn. control while previously reported oxyboration would give a 5-membered ring under kinetic control. The investigation of electrostatic potential maps suggested that the differences in the at. characters of indium, boron and their ligands would contribute to such a regioselective switch. and metalated isocoumarins were applied to organic synthetic reactions. The halogenation of metalated isocoumarins proceeded to afford 4-halogenated isocoumarins bearing various functional groups and palladium-catalyzed cross coupling of organometallic species with organic halides gave various 4-substituted isocoumarins. A formal total synthesis of oosponol, which exhibits strong antifungal activity, was accomplished. In addition to this study using Indium(III) bromide, there are many other studies that have used Indium(III) bromide(cas: 13465-09-3Synthetic Route of Br3In) was used in this study.
Indium(III) bromide(cas: 13465-09-3) is used as a catalyst to produce dithioacetals when unactivated alkynes react with thiols and fields such as optics and microelectronics that utilize semiconductor technology have wide uses for indium in high-performing solar cells.Synthetic Route of Br3In
Referemce:
Bromide – Wikipedia,
bromide – Wiktionary