The boraformylation of allenes with B2(pin)2 and a formate ester as boron and formyl source, respectively, proceeds in the presence of a copper catalyst. The reaction selectively affords the corresponding β‐boryl β,γ‐unsaturated aldehydes in good to high yields. Furthermore, the silaformylation of allenes was achieved with a formate ester and PhMe2Si−B(pin) as the silicon source.
The copper-catalyzed silylative allylation of ketones with allenes and silylboranes via an in situ generated β-silylallylcopper intermediate has been developed. Various ketones and allenes were converted to the homoallylic tertiary alcohols bearing internal (E)-vinylsilane moieties regio- and stereoselectively in good to high yields. Aldehydes were also employed as electrophiles in the reaction.
A regiodivergent silacarboxylation of allenes under a CO2 atmosphere with PhMe2Si-B(pin) as a silicon source in the presence of a copper catalyst at 70 °C has been developed. The regioselectivity of the reaction is successfully reversed by the proper choice of ligand; carboxylated vinylsilanes are obtained with rac-Me-DuPhos as the ligand, whereas the use of PCy3 affords carboxylated allylsilanes.
在 70 °C 下,在铜催化剂存在下,以 PhMe2Si-B(pin) 作为硅源,在 CO2 气氛下开发了丙二烯的区域发散硅羧化反应。反应的区域选择性通过适当的配体选择成功逆转; 使用 rac-Me-DuPhos 作为配体获得羧化乙烯基硅烷,而使用 PCy3 获得羧化烯丙基硅烷。因此,可以从单个丙二烯底物选择性地和区域发散地合成两种不同的羧化硅烷。
Copper-catalyzed hydroallylation of allenes employing hydrosilanes and allyl chlorides
The hydroallylation of allenes was developed by employing a hydrosilane and allylchlorides in the presence of a copper catalyst. The reaction provided (E)-1,5-dienes mainly in good to high yields.
Palladium-catalyzed formal arylacylation of allenes using acid chlorides and arylboronic acids has been achieved. The reaction afforded the corresponding alpha,beta-unsaturated ketones regio- and stereoselectively.