《Iridium-catalyzed C-H borylation of quinolines and unsymmetrical 1,2-disubstituted benzenes: insights into steric and electronic effects on selectivity》 was published in Chemical Science in 2012. These research results belong to Tajuddin, Hazmi; Harrisson, Peter; Bitterlich, Bianca; Collings, Jonathan C.; Sim, Neil; Batsanov, Andrei S.; Cheung, Man Sing; Kawamorita, Soichiro; Maxwell, Aoife C.; Shukla, Lena; Morris, James; Lin, Zhenyang; Marder, Todd B.; Steel, Patrick G.. Computed Properties of C14H21BO3 The article mentions the following:
Borylation of quinolines provides an attractive method for the late-stage functionalization of this important heterocycle. The regiochem. of this reaction is dominated by sterptsic factors but, by undertaking reactions at room temperature, an underlying electronic selectivity becomes apparent, as exemplified by the comparative reactions of 7-halo-2-methylquinoline and 2,7-dimethylquinoline which afford variable amounts of the 5- and 4-borylated products. Similar electronic selectivities are observed for nonsym. 1,2-disubstituted benzenes. The site of borylation can be simply estimated by anal. of the 1H NMR spectrum of the starting material with preferential borylation occurring at the site of the most deshielded sterically accessible H or C atom. Such effects can be linked with C-H acidity. While DFT calculations of the pKa for the C-H bond show good correlation with the observed selectivity, small differences suggest that related alternative, but much more computationally demanding values, such as the M-C bond strength, may be better quant. predictors of selectivity.2-(4-Methoxy-3-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(cas: 214360-63-1Computed Properties of C14H21BO3) was used in this study.
2-(4-Methoxy-3-methylphenyl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane(cas: 214360-63-1) belongs to ethers.Computed Properties of C14H21BO3Although ethers resist hydrolysis, they are cleaved by hydrobromic acid and hydroiodic acid. Hydrogen chloride cleaves ethers only slowly.
Referemce:
Ether – Wikipedia,
Ether | (C2H5)2O – PubChem