Regioselectivity Influences in Platinum-Catalyzed Intramolecular Alkyne O–H and N–H Additions
作者:Jeff P. Costello、Eric M. Ferreira
DOI:10.1021/acs.orglett.9b03557
日期:2019.12.20
The steric and electronic drivers of regioselectivity in platinum-catalyzed intramolecular hydroalkoxylation are elucidated. A branch point is found that divides the process between 5-exo and 6-endo selective processes, and enol ethers can be accessed in good yields for both oxygen heterocycles. The main influence arises from an electronic effect, where the alkyne substituent induces a polarization
different aromatic compounds 1a–1t with iodine and a mercury(II)-salt 2 [mercury(II) chloride, nitrate or triflate] (1:1:1 molar ratio) in dichloromethane at room temperature leads to the corresponding iodoarene 3, the obtained regiochemistry being the expected. Concerning the mercury(II) salt, the observed reactivity decreased in the series triflate&>nitrate&>chloride according to their ionic character.
Progressive Direct Iodination of Sterically Hindered Alkyl Substituted Benzenes
作者:Stojan Stavber、Petra Kralj、Marko Zupan
DOI:10.1055/s-2002-33339
日期:——
Benzene derivatives bearing at least one bulky alkyl group (i-Pr or t-Bu) were selectively and effectively iodinated using elemental iodine activated by 1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis(tetrafluoroborate) (Selectfluor, F-TEDA-BF 4 ). Iodine atoms were progressively introduced at the most electron-rich and sterically less hindered position on the benzene ring. Not more than