Selective ethylation and vinylation of alkanes via polyoxotungstate photocatalyzed radical addition reactions

Polyoxotungstate Photoinduced Alkylation of Electrophilic Alkenes by Cycloalkanes

“…[8] Such addition processes are interesting as a way for the direct functionalization of inactivated CÀH bonds, but occur slowly (F < 0.05) and only up to a low extent. As an example, Hill reported that ethylcyclohexane is formed from cyclohexane and ethene with 83 % selectivity and 8±9 % conversion after 78 h, and conversion could not be brought over 10 %.…”

“…As an example, Hill reported that ethylcyclohexane is formed from cyclohexane and ethene with 83 % selectivity and 8±9 % conversion after 78 h, and conversion could not be brought over 10 %. [8] This is probably due to the ™persistent radical effect∫, [7b, 17] namely to the fact that, while highly reactive alkyl radicals are consumed through various paths (dimerization, disproportionation to alkenes and other unidentified), a more persistent species such as H + W 10 O 32 5À builds up and this in turn increases the role of reverse reactions such as that in eq. 2, thus inhibiting the progress of the addition.…”

“…[2,7] As for the reactions of the alkane, it has been demonstrated that alkyl radicals add to ethylene, 1-hexene, acetylene, [8] carbon monoxide, [9] nitriles [10] and cyanoformate [11] forming a CÀC bond, besides adding to oxygen to give hydroperoxides and alcohols and ketones from them. [7,12] Somewhat surprising, the most typical reaction of alkyl radicals, addition to electrophilic alkenes [13] has not been explored.…”

Site-selectivity in TBADT-photocatalyzed C(sp3)–H Functionalization of Saturated Alcohols and Alkanes

“…Previous works reported on methine CH functionalization with 2-methylpropane, 11 2,3-dimethylbutane, 12 and 2,4-dimethylpentane. 4a The reaction of hexane (1i) with dimethyl maleate (2e) proceeded without site-selectivity to give a mixture of three regioisomers resulting from the functionalization of the 1-, 2-, and 3-positions in an 8/67/25 ratio (Table 2, Entry 1).…”

Atom‐Economical Synthesis of Unsymmetrical Ketones through Photocatalyzed CH Activation of Alkanes and Coupling with CO and Electrophilic Alkenes

“…[7,8] This species has recently attracted attention because of the high photoactivity in the CÀH bond homolytic hydrogen abstraction in alkanes [9] and in other substrates including aldehydes [10] and amides. [11] We supposed that a three-component coupling reaction through alkane C À H cleavage under photocatalysis by TBADT and a radical carbonylation would lead to the desired products.…”