Catalytic Transformations of Alkynes into either α-Alkoxy or α-Aryl Enolates: Mannich Reactions by Cooperative Catalysis and Evidence for Nucleophile-Directed Chemoselectivity
作者:Rajkumar Lalji Sahani、Manoj D. Patil、Sachin Bhausaheb Wagh、Rai-Shung Liu
DOI:10.1002/anie.201806883
日期:2018.11.5
The catalytic formation of gold enolatesfrom alkynes, nitrones, and nucleophiles is described, and their Mannich reactions result in nucleophile‐directed chemoselectivity through cooperative catalysis. For 1‐alkyn‐4‐ols and 2‐ethynylphenols, their gold‐catalyzed nitrone oxidations afforded N‐containing dihydrofuran‐3(2H)‐ones with syn selectivity. The mechanism involves the Mannich reactions of gold
Synthese und Eigenschaften von<i>o</i>-hydroxyphenyl- und<i>o</i>-acetylaminophenyl-substituierten Cyclopropenonen. Eine neuartige thermische Umwandlung funktionalisierter Diarylcyclopropenone
作者:Theophil Eicher、Volker Schneider
DOI:10.1055/s-1989-27255
日期:——
Synthesis and Properties of o-Hydroxyphenyl- and o-Acetylaminophenyl-Substituted Cyclopropenones. A Novel Thermal Transformation of Functionalized Cyclopropenones The ortho-functionalized arylphenylcyclopropenones 3 are prepared via the West method and their spectroscopic and chemical properties are reported. The cyclopropenones 3 undergo thermal transformation to give heterocycles 7, 8, 12, photochemically they are decarbonylated to give alkynes 9 as main products. The structures of the heterocycles 7, 8, 12 are proven by means of spectroscopic data and by independent synthesis. A mechanism for this novel thermal cyclopropenone transformation is discussed.