Umpolung reactivity in amide and peptide synthesis
作者:Bo Shen、Dawn M. Makley、Jeffrey N. Johnston
DOI:10.1038/nature09125
日期:2010.6
which the polarities of the two reactants are reversed (German, umpolung) during carbon–nitrogen bond formation relative to traditional approaches. The use of nitroalkanes as acyl anion equivalents provides a conceptually innovative approach to amide and peptide synthesis, and one that might ultimately provide for efficient peptide synthesis that is fully reliant on enantioselective methods.
The Selective<i>N</i>-Monoalkylation of Amides with Alkyl Halides in the Presence of Alumina and KOH
作者:Kazuaki Sukata
DOI:10.1246/bcsj.58.838
日期:1985.3
The effects of alumina impregnated with KOH (KOH/Al2O3) and a mixture of alumina and powdered KOH (KOH+Al2O3) have been examined using the alkylation of benzamide under various conditions. In each case, alkylation occurs exclusively in the pores of the alumina, the extent depending upon the alumina-pore size. For both yield and selectivity for N-monoalkylation, KOH+Al2O3 is superior to KOH/Al2O3. Dioxane is the best of the solvents employed. It is proposed that, in dioxane, an enolate-like species, (Remark: Graphics omitted.), exists as stable ion-pair aggregates, which are the true reactants in the pore. This method, using KOH/Al2O3 or KOH+Al2O3, has been applied to N-alkylation of the other amides, giving the N-monoalkylated products in substantial yields with extremely high selectivities. 2-Phenylacetamide is regioselectively N-monoalkylated in high yields. This regioselectivity is explained in terms of steric hindrance.
Visible-light-induced installation of oxyfluoroalkyl groups
作者:Gwi-Rim Park、Jisu Moon、Eun Jin Cho
DOI:10.1039/c7cc08067k
日期:——
(Hetero)aryloxytetrafluoroethylation of heteroaromatics and alkenes has been achieved by visible-light photocatalysis utilizing readily synthesized oxyfluoroalkyl reagents.
利用易于合成的氧氟代烷基试剂,通过可见光光催化实现了杂芳环和烯烃的(杂)芳氧基四氟乙基化。
Visible-Light-Induced Trifluoromethylation of Unactivated Alkenes with Tri(9-anthryl)borane as an Organophotocatalyst
作者:Jisu Moon、Yu Kyung Moon、Do Dam Park、Sukyung Choi、Youngmin You、Eun Jin Cho
DOI:10.1021/acs.joc.9b01624
日期:2019.10.18
applied as an organophotocatalyst for the visible-light-induced trifluoromethylation of unactivated alkenes with CF3I. The mild reaction conditions tolerated a variety of functional groups, and the reaction could be extended to perfluoroalkylations with C3F7I and C4F9I. Mechanistic studies revealed that the photoredox catalysis involves an oxidative quenching pathway.
The formation of amides through the in situactivation of carboxylicacids with [Et2NSF2]BF4 is presented. A wide range of carboxylicacids and amines were used to produce the corresponding amides in up to 99 % yield. The reaction of hindered amines was also possible in the presence of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) under slightly modified conditions. An enantiopure carboxylicacid and amine