<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 Annulation of Bromoenal and 1,3-Dicarbonyl Compounds
作者:Fang-Gang Sun、Li-Hui Sun、Song Ye
DOI:10.1002/adsc.201100622
日期:2011.11
Highly enantioselective [3+3] annulation reactions of bromoenals and 1,3-dicarbonylcompounds are reported. In addition, both enantiomers of the resultant dihydropyranone could be easily obtained by choosing N-heterocyclic carbenes (NHCs) with the same stereocenter but different substituents under the optimized reaction conditions.
Regioselective synthesis of α-bromo-α,β-unsaturated carbonyl compounds via photocatalytic α-bromination reactions
作者:Dan Wang、Yating Zhao、Chao Yang、Wujiong Xia
DOI:10.1007/s11426-015-5530-7
日期:2016.2
A visible light-mediated approach for the preparation of α-bromo-α,β-unsaturated ketones and aldehydes was developed. In comparison to traditional methods that generally take two steps to afford the above compounds, this protocol was highlighted by its operational simplicity, avoiding using hazardous bromine and mild reaction conditions.
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