我们报告了一种单一的添加剂响应型铬催化系统,用于选择性生产两种不同的内部烯烃异构体中的任何一种。在 HBpin/LiO t Bu 存在下,铬催化剂能够使烯烃在多个碳原子上异构化,得到热力学最稳定的异构体。同一催化剂无需添加剂即可实现末端烯烃在一个碳原子上的选择性异构化,表现出高效且可控的烯烃转位选择性。
Asymmetric Cross-coupling of Potassium 2-Butenyltrifluoroborates with Aryl and 1-Alkenyl Bromides Catalyzed by a Pd(OAc)<sub>2</sub>/Josiphos Complex
作者:Yasunori Yamamoto、Shingo Takada、Norio Miyaura
DOI:10.1246/cl.2006.1368
日期:2006.12
The asymmetric cross-coupling reaction of [CH3CH=CHCH2BF3]K with aryl or 1-alkenyl bromides selectively occurred at the γ-carbon of 2-butenylborane moiety with regioselectivities in a range of 84–99%. The enantioselectivities were in a range of 77–90%ee when a palladium/CyPF-t-Bu complex was used at 80 °C in the presence of K2CO3 (3 equiv.) in H2O–MeOH (9/1).
Tertiary Amines Acting as Alkyl Radical Equivalents Enabled by a P/N Heteroleptic Cu(I) Photosensitizer
作者:Limeng Zheng、Qinfang Jiang、Hanyang Bao、Bingwei Zhou、Shu-Ping Luo、Hongwei Jin、Huayue Wu、Yunkui Liu
DOI:10.1021/acs.orglett.0c03236
日期:2020.11.20
An unprecedented exploration of tertiary amines as alkyl radical equivalents for cross-coupling with aromatic alkynes to access allylarenes has been achieved by a P/N heteroleptic Cu(I)-based photosensitizer under photoredox catalysis conditions. Mechanistic studies reveal that the reaction might undergo radical addition of in situ-generated α-amino radical intermediates to alkynes followed by 1,5-hydrogen
The fluoride free cross-coupling between aryldimethylsilanes and organic halides proceeded in the presence of monocopper(i) alkoxide of ethylene glycol. The similar reaction of alkenyldimethylsilanes also took place with complete retention of configuration.
of two different internal alkene isomers. The chromium catalyst, in the presence of HBpin/LiOtBu, enables the isomerization of alkenes over multiple carbon atoms to give the most thermodynamically stable isomers. The same catalyst allows for the selective isomerization of terminal alkenes over one carbon atom without an additive, exhibiting efficient and controllable alkene transposition selectivity
我们报告了一种单一的添加剂响应型铬催化系统,用于选择性生产两种不同的内部烯烃异构体中的任何一种。在 HBpin/LiO t Bu 存在下,铬催化剂能够使烯烃在多个碳原子上异构化,得到热力学最稳定的异构体。同一催化剂无需添加剂即可实现末端烯烃在一个碳原子上的选择性异构化,表现出高效且可控的烯烃转位选择性。