开发了三齿 PSiP 钳形钯配合物在二氧化碳下催化丙二烯加氢羧化,得到合成有用的 β, γ-不饱和羧酸。这种新型的 CO2 固定反应被认为是通过丙二烯的氢化钯催化生成 σ-烯丙基钯物种,然后在适当的还原剂存在下将其区域选择性亲核加成到 CO2 中进行的。该反应成功应用于带有酯、氨基甲酸酯、酮和烯烃等官能团的各种丙二烯,显示出该方案的高合成效用。
开发了三齿 PSiP 钳形钯配合物在二氧化碳下催化丙二烯加氢羧化,得到合成有用的 β, γ-不饱和羧酸。这种新型的 CO2 固定反应被认为是通过丙二烯的氢化钯催化生成 σ-烯丙基钯物种,然后在适当的还原剂存在下将其区域选择性亲核加成到 CO2 中进行的。该反应成功应用于带有酯、氨基甲酸酯、酮和烯烃等官能团的各种丙二烯,显示出该方案的高合成效用。
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.
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。
Gold(I)-catalysed iodoalkoxylation of allenes
作者:Amelie Heuer-Jungemann、Ross G. McLaren、Maximillian S. Hadfield、Ai-Lan Lee
DOI:10.1016/j.tet.2011.01.021
日期:2011.3
Gold(I)-catalysed intermolecular iodoalkoxylation of allenes occurs in a regioselective and stereoselective manner to produce versatile iodo-tert-allyllic ether products. The products can be further elaborated through cross-couplings to yield highly substituted tert-allylic ethers.
Regioselective Synthesis of <i>tert</i>-Allylic Ethers via Gold(I)-Catalyzed Intermolecular Hydroalkoxylation of Allenes
作者:Maximillian S. Hadfield、Ai-Lan Lee
DOI:10.1021/ol902675k
日期:2010.2.5
A highly regioselective method towards tertiary allylic ethers via gold(I)-catalyzed intermolecular hydroalkoxylation of allenes is disclosed. Preventing subsequent isomerization of the tertiary allylic ether products to primary allylic ethers appears to be the key to achieving high regioselectivities.
The unprecedented radical β-elimination of vinylsulfoxides opens a new access to functionalized di- and trisubstituted allenes. The radical precursors are obtained in two steps from a carbonyl derivative and a vinylsulfoxide. The radical translocation trick can also be used to trigger the β-elimination of the sulfinyl radical.