Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron...Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.展开更多
We report a transition-metal-free and bis(pinacolato)diborane(B_(2)Pin_(2))-promoted transfer hydrogenation of various alkynes to alkanes in high yields with methanol as hydrogen source under mild reaction conditions....We report a transition-metal-free and bis(pinacolato)diborane(B_(2)Pin_(2))-promoted transfer hydrogenation of various alkynes to alkanes in high yields with methanol as hydrogen source under mild reaction conditions.Control experimental results revealed that bis(pinacolato)diborane and methanol played important roles for the transfer hydrogenation of alkynes to alkanes.It is shown that in situ generated borane was the key reductant for the activated alkynes whereas bis(pinacolato)diborane served as strong Lewis acid reagents for diarylacetylenes.More importantly,these transfer hydrogenations could be applied into modifying natural products and a CF_(3)-substituted alkyl group could be easily introduced into complex molecules.The present method highlights mild reaction conditions,broad substrate scope of alkynes,transition-metal free transfer hydrogenation,and gram scalable preparations without column chromatography.展开更多
文摘Organoboron compounds have become important intermediates for the construction of new compounds in synthetic chemistry and pharmaceutical chemistry,and it has been found that pinacol biborate(B_(2)pin_(2))as the boron source and Cu^(Ⅱ) organophosphorus complex(L)as the catalyst can effectively realize the hydrogen-reduced borylation products and dehydrohydrated borylation products of aryl olefins.The reaction regioselectivity involvingβ-C positions of aryl olefins can be controlled by regulating the ligand and additive types.The formation mechanism of the product is conducted at LCu^(Ⅰ)Bpin formed from Cu^(Ⅱ),L and B_(2)pin_(2).Subsequently the substrate aryl olefins undergo addition reaction to form the active intermediate PhCH(LCu^(Ⅰ))CH_(2)Bpin.Followed by the metathesis of the active intermediate with water to form hydrogen reduction products,the same active intermediate can be oxidized with 2,2,6,6-tetramethylpiperidoxyl(TEMPO)to form trans dehydrogenation products.
基金Financial support from the National Natural Science Foundation of China(2257105O)Natural Science Foundation of Guangxi Province(2025GXNSFGA069003,2025GXNSFBA069568,2023GXNSFDA026025)+1 种基金Innovation Project of Guangxi Graduate Education(XYCS2025104)Guangxi Bagui Youth Program is greatly appreciated.
文摘We report a transition-metal-free and bis(pinacolato)diborane(B_(2)Pin_(2))-promoted transfer hydrogenation of various alkynes to alkanes in high yields with methanol as hydrogen source under mild reaction conditions.Control experimental results revealed that bis(pinacolato)diborane and methanol played important roles for the transfer hydrogenation of alkynes to alkanes.It is shown that in situ generated borane was the key reductant for the activated alkynes whereas bis(pinacolato)diborane served as strong Lewis acid reagents for diarylacetylenes.More importantly,these transfer hydrogenations could be applied into modifying natural products and a CF_(3)-substituted alkyl group could be easily introduced into complex molecules.The present method highlights mild reaction conditions,broad substrate scope of alkynes,transition-metal free transfer hydrogenation,and gram scalable preparations without column chromatography.
