Making kinetic and thermodynamic enolates via solvent-free high speed ball milling
作者:Daniel C. Waddell、Indre Thiel、Tammara D. Clark、S. Tyler Marcum、James Mack
DOI:10.1039/b922108p
日期:——
solvent-free high speed ball milling conditions. Using 2-methylcyclohexanone as the substrate and sodium hydroxide or lithium hexamethyldisilazide as the base, we were able to trap the thermodynamic or kinetic enolate in high selectivity. Although all the reagents were ball milled simultaneously, we observed no products resulting from aldol condensation.
Investigating the formation of dialkyl carbonates using high speed ball milling
作者:Daniel C. Waddell、Indre Thiel、Ashley Bunger、Dominique Nkata、Ashley Maloney、Tammara Clark、Brandon Smith、James Mack
DOI:10.1039/c1gc15594f
日期:——
We investigated the synthesis of dialkyl carbonates under solvent-free high speed ball milling conditions. We converted various metal carbonates with the assistance of metal complexing reagents into a variety of dialkyl carbonates. We also observed the increased reactivity of urea under similar reaction conditions.
Metal-Free Synthesis of Cyclic and Acyclic Carbonates from CO<sub>2</sub>and Alcohols
作者:Yu Na Lim、Chan Lee、Hye-Young Jang
DOI:10.1002/ejoc.201400031
日期:2014.3
Diverse cyclic and acyclic carbonates such as ethylene carbonate, propylene carbonate, glycerol carbonate, and dimethyl carbonate were synthesized in moderate to good yields by the direct coupling of the corresponding alcohols with carbon dioxide in the absence of metal catalysts and inorganic bases. The direct carbonation mechanism of alcohols in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene
Chiral 1,2,3‐Triazolium Salt Catalyzed Asymmetric Mono‐ and Dialkylation of 2,5‐Diketopiperazines with the Construction of Tetrasubstituted Carbon Centers
作者:Ju‐Song Yang、Ka Lu、Chen‐Xiao Li、Zu‐Hang Zhao、Xiao‐Ming Zhang、Fu‐Min Zhang、Yong‐Qiang Tu
DOI:10.1002/anie.202114129
日期:2022.2.21
Chiral spirocyclic-amide-derived triazolium salts were used as new phase-transfer organocatalysts for asymmetric alkylation to construct 2,5-diketopiperazine motifs containing one or two tetrasubstituted carbon centers in high yields with excellent cis-diastereoselectivity and enantioselectivity. Control experiments and DFT calculations revealed the possible reaction mechanism and the origins of the