Direct Amination of Homoenolates Catalyzed by <i>N</i>-Heterocyclic Carbenes
作者:Audrey Chan、Karl A. Scheidt
DOI:10.1021/ja711130p
日期:2008.3.1
beta-unsaturated aldehydes and acylaryldiazenes, catalyzed by an N-heterocycliccarbene, produces substituted pyrazolidinones in good yields. This new NHC-catalyzed reaction accommodates aromatic and alkyl alpha,beta-unsaturated aldehydes and various aromatic diazenes. A chiral triazolium salt catalyzes the formation of the pyrazolidinone product in moderate yield and good enantioselectivity. The pyrazolidinones
Asymmetric NHC-Catalyzed Redox α-Amination of α-Aroyloxyaldehydes
作者:James E. Taylor、David S. B. Daniels、Andrew D. Smith
DOI:10.1021/ol402955f
日期:2013.12.6
(NHC)-catalyzed redox reaction of α-aroyloxyaldehydes with N-aryl-N-aroyldiazenes to form α-hydrazino esters with highenantioselectivity (up to 99% ee) is reported. The hydrazide products are readily converted into enantioenriched N-aryl amino esters through samarium(II) iodidemediated N–N bond cleavage.
2-Arylacetic anhydrides as ammonium enolate precursors
作者:Louis C. Morrill、Lyndsay A. Ledingham、Jean-Philippe Couturier、Jasmine Bickel、Andrew D. Harper、Charlene Fallan、Andrew D. Smith
DOI:10.1039/c3ob41869c
日期:——
Readily prepared 2-arylacetic anhydrides act as convenient ammonium enolate precursors in isothiourea (HBTM-2.1)-mediated catalytic asymmetric intermolecular Michael addition–lactonisation processes, giving diverse synthetic building blocks in good yield with high diastereo- and enantiocontrol (up to 98 : 2 dr and >99% ee).
在异硫脲(HBTM-2.1)介导的催化不对称分子间迈克尔加成-内酯化过程中,容易制备的 2-芳基乙酸酐可作为方便的烯酸铵前体,以良好的收率和较高的非对映及对映控制(高达 98 : 2 dr 和 >99% ee)提供多种合成构件。
A Deoxygenative [4+1] Annulation Involving<i>N</i>-Acyldiazenes for an Efficient Synthesis of 2,2,5-Trisubstituted 1,3,4-Oxadiazole Derivatives
作者:Rong Zhou、Ling Han、Honghui Zhang、Rongfang Liu、Ruifeng Li
DOI:10.1002/adsc.201700935
日期:2017.11.23
+ 1] annulation of N-acyldiazenes with α-dicarbonyl compounds such as isatins, α-keto esters, and α-diketones is reported. The annulation reactions proceed smoothly under mild conditions to deliver a broad range of 2,2,5-trisubstituted 1,3,4-oxadiazole derivatives in moderate to excellent yields from readily available starting materials. It represents the first realization of the [4+1] annulation mode
Azoolefins 2 either decompose or react with aryldiiminea with uptake of an aryl group to give compounds 3. The latter can undergo ringclosure to N-amino-indoles 4. In the 2,4,6-trichloro compound 3b ortho-chlorines are selectively replaced bymorpholine under very mild conditions giving 5a, which easily fragments to form the benzimidazole 7.