Synthesis of Six-Membered Compounds by Environmentally Friendly Cyclization Using Indirect Electrolysis
摘要:
[Ni(cyclam)](ClO4)(2)-catalyzed indirect electroreduction of olefinic bromides produced six-membered compounds in low to high yields. The synthetic intermediate 49 of Ipecac and Corynanthe alkaloids was obtained in 88% yield in a highly stereoselective manner. Lactam 66, the synthetic precursor of tacamonine, was prepared in 49% yield as a mixture of two diastereoisomers. The electrolysis of the bromoacetates gave the debrominated compounds in good yields.
Radical-Organometallic Hybrid Reaction System Enabling Couplings between Tertiary-Alkyl Groups and 1-Alkenyl Groups
摘要:
Suzuki-Miyaura couplings of tertiary-alkyl moieties are accomplished in the presence of a copper catalyst, in which quaternary carbons possessing various functional groups can be synthesized via a radical reaction. Mechanistic studies revealed that 1-alkenylcopper(I) plays an important role in this coupling reaction. We expect that the radical-organometallic combined process will become one of the best options for the synthesis of quaternary carbons.
Palladium-Catalyzed Intermolecular Heck-Type Reaction of Epoxides
作者:Shenghan Teng、Malcolm E. Tessensohn、Richard D. Webster、Jianrong Steve Zhou
DOI:10.1021/acscatal.8b02029
日期:2018.8.3
palladium-catalyzed intermolecular Heck-type reaction of both cyclic and acyclic epoxides is reported with tolerance of typical polar groups and acidic protons. Suitable alkenes include styrenes, conjugate dienes, and some electron-deficient olefins. In reactions of aliphatic terminal epoxides, ring opening occurs selectively at terminal positions, and stereocenters of epoxides are fully retained. Mechanistic studies
[Ni(cyclam)](ClO4)(2)-catalyzed indirect electroreduction of olefinic bromides produced six-membered compounds in low to high yields. The synthetic intermediate 49 of Ipecac and Corynanthe alkaloids was obtained in 88% yield in a highly stereoselective manner. Lactam 66, the synthetic precursor of tacamonine, was prepared in 49% yield as a mixture of two diastereoisomers. The electrolysis of the bromoacetates gave the debrominated compounds in good yields.
Radical-Organometallic Hybrid Reaction System Enabling Couplings between Tertiary-Alkyl Groups and 1-Alkenyl Groups
Suzuki-Miyaura couplings of tertiary-alkyl moieties are accomplished in the presence of a copper catalyst, in which quaternary carbons possessing various functional groups can be synthesized via a radical reaction. Mechanistic studies revealed that 1-alkenylcopper(I) plays an important role in this coupling reaction. We expect that the radical-organometallic combined process will become one of the best options for the synthesis of quaternary carbons.