PCy<sub>3</sub>-Catalyzed Ring Expansion of Aziridinofullerenes with CO<sub>2</sub>and Aryl Isocyanates: Evidence for a Two Consecutive Nucleophilic Substitution Pathway on the Fullerene Cage
作者:Youhei Takeda、Hajime Kawai、Satoshi Minakata
DOI:10.1002/chem.201301617
日期:2013.9.27
PCy3‐catalyzed ring‐expansion reaction of aziridine‐fused fullerenes (aziridinofullerenes) through the insertion of CO2 and arylisocyanates is disclosed. The reaction allows for CO2 fixation by aziridinofullerenes, producing oxazolidinone‐fused fullerenes (oxazolidinofullerenes) in high yields, whereas treatment with arylisocyanates led to a new fullerene family—imidazolidinone‐fused fullerenes (imidaz
A new bromoform reaction of tertiary amines with N,N-dibromosulfonamides or NBS/sulfonamides has been developed. A series of amidines were prepared with moderate to good yields via a Csp(3)-Csp(3) bond cleavage.
TsNBr2 reacts readily with olefins to produce α-bromo ketones at room temperature. The synthesis was carried out by treating an olefin with TsNBr2 in acetone–water mixture in 30:1 ratio. Excellent yield of corresponding α-bromo ketone could be achieved within a short time.
Unprecedented 1,3-<i>tert</i>-butyl migration <i>via</i> the C–N single bond scission of isonitrile: an expedient metal-free route to <i>N</i>-sulfonyl amidines
isonitrile with N,N-dibromoaryl sulfonamides and nitrile. The reaction involves the simultaneous C–N single bond scission of isonitrile and the migration of the tert-alkyl group to the adjacent unsaturated nitrogen centre of the nitrile precursor, which eventually results in the formation of N-sulfonyl amidine. This method constitutes a new route for sulfonyl amidine, which does not rely on transition metals
Atmosphere- and Temperature-Controlled Regioselective Aminobromination of Olefins
作者:Wesley Zongrong Yu、Yi An Cheng、Ming Wah Wong、Ying-Yeung Yeung
DOI:10.1002/adsc.201600821
日期:2017.1.19
A complete switch of regioselectivity in the aminobromination of olefins is realized from delicate changes in the reaction temperature from 25 °C to 40 °C and the atmosphere from air to argon, under catalyst‐free conditions. The resulting α‐bromoamides can be transformed easily to high‐value compounds (e.g., Clobenzorex). Mechanistic studies revealed that the reaction went through a radical pathway