52380-85-5Relevant academic research and scientific papers
Pd-Catalyzed Cyclization of Alkynyl Norbornene Derivatives for the Synthesis of Benzofused Heteroarenes
Kwak, Hayeon,Kang, Eunsu,Song, Jae Yeong,Kang, Geunhee,Joo, Jung Min
supporting information, p. 4883 - 4888 (2021/09/09)
Modular approaches, which allow a systematic variation of heteroaromatic cores and substituents, are crucial for the development of heteroaromatic drug candidates and organic functional materials. A new strategy involving the cyclization of heteroarenes tethered with alkynes through a norbornene bridge was developed. The precursors were readily prepared by a three-component coupling process of heteroaryl halides, norbornadiene, and terminal alkynes. The Pd catalytic system derived from Pd(OAc)2 and 2-(pyrazol-1-yl)pyridine transformed a variety of five-membered heteroarenes to the corresponding benzofused products, including (di)benzothiophene, indazole, carbazole, indole, and benzofuran, with aryl and alkyl substituents at the C4(C7) position. During the cyclization process, the norbornene ring underwent a retro-Diels-Alder reaction, serving as an acetylene synthon. This approach was used to synthesize naphthalene derivatives from electron-rich arenes, demonstrating its versatility in the annulation of (hetero)aromatic rings. (Figure presented.).
Unexpected formation of 4,7-dihalobenzo[b]thiophenes using Ohira-Bestmann reagent and reactivity of the halogen-substituted benzo[b]thiophenes in Suzuki-Miyaura coupling with phenylboronic acid
Toyota, Kozo,Mutoh, Hirotaka,Kishi, Hiroki,Mikami, Shinichi,Tanaka, Hiroki,Yoshida, Shuhei,Naganuma, Daisuke
, p. 1355 - 1374 (2019/12/23)
Reaction of 2-(1-adamantylsulfanyl)-3,6-dihalobenzaldehydes with Ohira-Bestmann reagent gave 4,7-dihalobenzo[b]thiophenes along with normal alkyne products. Nine types of 4,7-dihalobenzo[b]thiophenes bearing chlorine, bromine, or iodine atoms, were prepared by this method. Regioselectivity in Suzuki-Miyaura cross coupling reactions of the 4,7-dihalobenzo[b]thiophenes with PhB(OH)2 was also studied.
Chemoselective Synthesis of Polysubstituted Pyridines from Heteroaryl Fluorosulfates
Zhang, Enxuan,Tang, Jiaze,Li, Suhua,Wu, Peng,Moses, John E.,Sharpless, K. Barry
supporting information, p. 5692 - 5697 (2016/04/20)
A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib. A selection of heteroaryl fluorosulfates were readily synthesized using commercial SO2F2 gas. These substrates are highly efficient coupling partners in the Suzuki reaction. Through judicious selection of Pd catalysts the fluorosulfate functionality is differentiated from bromide and chloride; the order of reactivity being: -Br> -OSO2F> -Cl. Exploiting this trend allowed the stepwise chemoselective synthesis of a number of polysubstituted pyridines, including the drug Etoricoxib.
