<scp>DMAP‐Catalyzed</scp>
C—N Bond Formation for Diverse Synthesis of Imidazo[1,2‐
<i>a</i>
]pyrimidine and Pyrimido[1,2‐
<i>a</i>
]benzimidazole Derivatives
作者:Le‐Le Shang、Yun Feng、Xing‐Lian Gao、Zi‐Ren Chen、Yu Xia、Wei‐Wei Jin、Chen‐Jiang Liu
DOI:10.1002/cjoc.202000214
日期:2020.12
A DMAP (2‐dimethylaminopyridine)‐catalyzed condensation reactions for the successful direct construction of pyrimido[1,2‐a]benzimidazole or imidazo[1,2‐a]pyrimidine has been developed. The method utilizes readily available α‐bromocinnamaldehydes with 2‐aminobenzimidazole or 2‐aminoimidazole as starting materials in the presence of 2‐DMAP/TBHP. In the process, two C—N bonds were successfully constructed
Aminothiolation of α-Bromocinnamaldehydes to Access Imidazo[2,1-<i>b</i>]thiazoles by Incorporation of Two Distinct Photoinduced Processes
作者:Ziren Chen、Weiwei Jin、Yu Xia、Yonghong Zhang、Mengwei Xie、Shangchao Ma、Chenjiang Liu
DOI:10.1021/acs.orglett.0c02907
日期:2020.11.6
visible-light-promoted metal-free catalytic system was developed to achieve the aminothiolation of α-bromocinnamaldehydes. This mechanistically novel approach allows the synthesis of diverse imidazo[2,1-b]thiazole derivatives in satisfactory yields at room temperature under visible-light irradiation by incorporation of two distinct photoinduced processes. The reaction features readily accessible feedstocks
开发了可见光促进的无金属催化体系,以实现α-溴肉桂醛的氨基硫醇化。这种机制新颖的方法允许通过掺入两种不同的光诱导过程,在室温下在可见光照射下以令人满意的产率合成各种咪唑并[2,1- b ]噻唑衍生物。该反应具有容易获得的原料,易于操作,温和的反应条件和广泛的反应范围的特征。
N-Heterocyclic Carbene-Catalyzed Enantioselective Synthesis of Spiro-glutarimides via α,β-Unsaturated Acylazoliums
作者:Santigopal Mondal、Arghya Ghosh、Subrata Mukherjee、Akkattu T. Biju
DOI:10.1021/acs.orglett.8b01799
日期:2018.8.3
NHC-catalyzed enantioselective [3 + 3] spiro-annulation of α,β-unsaturated aldehydes with cyclic β-ketoamides allowing the preparation of synthetically and biologically important spiro-glutarimide derivatives has been reported. The interception of the ketoamides with catalytically generated chiral α,β-unsaturatedacylazoliums proceeds in a Michael addition–intramolecular amidation pathway to deliver
NHC-Catalyzed [3 + 3] Annulation of Thioamides and Modified Enals for the Enantioselective Synthesis of Functionalized Thiazinones
作者:Arghya Ghosh、Soumen Barik、Akkattu T. Biju
DOI:10.1021/acs.orglett.9b03188
日期:2019.11.1
(NHC)-catalyzed [3 + 3] annulation of thioamides with modified enals allowing the enantioselective synthesis of functionalized 1,3-thiazin-4-ones is reported. The NHC generated from the chiral triazolium salt was optimal and the reaction is initiated by the thia-Michael addition to catalytically generated α,β-unsaturated acylazolium intermediates derived from 2-bromoenals, followed by intramolecular cyclization
Enantioselective Synthesis of Tricyclic β-Lactones by NHC-Catalyzed Desymmetrization of Cyclic 1,3-Diketones
作者:Sayan Shee、Subrata Mukherjee、Rajesh G. Gonnade、Akkattu T. Biju
DOI:10.1021/acs.orglett.0c01756
日期:2020.7.17
The NHC-catalyzed desymmetrization of cyclic-1,3-diketones allowing the enantioselective construction of tricyclic β-lactones with five contiguous stereocenters, including two quaternary stereocenters, has been developed. The mild and operationally simple addition of α-bromoenals to cyclopentane-1,3-diketone derivatives proceeds via the initial formation of chiral α,β-unsaturated acylazolium intermediates