1311291-96-9Relevant academic research and scientific papers
Kinetic Resolution by Lithiation: Highly Enantioselective Synthesis of Substituted Dihydrobenzoxazines and Tetrahydroquinoxalines
El-Tunsi, Ashraf,Carter, Nicholas,Yeo, Song-Hee,Priest, Joshua D.,Choi, Anthony,Kobras, Carolin M.,Ndlovu, Soneni,Proietti Silvestri, Ilaria,Fenton, Andrew K.,Coldham, Iain
, p. 355 - 368 (2021/11/13)
Kinetic resolution provided a highly enantioselective method to access a range of 3-aryl-3,4-dihydro-2H-1,4-benzoxazines using n-butyllithium and the chiral ligand sparteine. The enantioenrichment remained high on removing the tert-butoxycarbonyl (Boc) protecting group. The intermediate organolithium undergoes ring opening to an enamine. The kinetic resolution was extended to give enantiomerically enriched substituted 1,2,3,4-tetrahydroquinoxalines and was applied to the synthesis of an analogue of the antibiotic levofloxacin that was screened for its activity against the human pathogen Streptococcus pneumoniae.
An organocatalyst bearing stereogenic carbon and sulfur centers as an efficient promoter for enantioselective hydrosilylation of 1,4-benzooxazines
Liu, Xiang-Wei,Wang, Chao,Yan, Yan,Wang, Yong-Qiang,Sun, Jian
, p. 6276 - 6280 (2013/07/26)
The efficient and enantioselective hydrosilylation of 3-aryl-1,4- benzooxazines was achieved using an l-phenyl alanine derived new Lewis base catalyst bearing stereogenic carbon and sulfur centers. In the presence of 2 mol % of catalyst, a broad range of 3-aryl-1,4-benzooxazines were hydrosilylated to afford the corresponding chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazine products with good to high yields (66-98%) and enantioselectivities (70-99% ee). This method provides an alternative approach with great practical application potential to access chiral 3-aryl-3,4-dihydro-2H-1,4-benzooxazines.
First I2-K2CO3-promoted sequential C-N and C-O bond forming approach for one-pot synthesis of 1,4-benzoxazines
Singh, Sunil K.,Bajpai, Anil K.,Saini, Rajesh
, p. 7132 - 7135 (2013/12/04)
I2-K2CO3 combination has been found to be an efficient, reusable, and inexpensive catalyst system for the one-pot synthesis of 3-aryl-2H-benz[1,4]oxazine via rapid CN and C-O bond formation. No by-product formation, operat
Lewis base organocatalyzed enantioselective hydrosilylation of 1,4-benzoxazines
Jiang, Yan,Liu, Li-Xin,Yuan, Wei-Cheng,Zhang, Xiao-Mei
supporting information; experimental part, p. 1797 - 1800 (2012/08/29)
A chiral Lewis base organocatalyzed enantioselective hydrosilylation of 1,4-benzoxazines is presented. The reactions afforded various enantioenriched 3-substituted dihydro-2H-1,4-benzoxazines with high yields (up to 98%) in moderate enantioselectivities (up to 87% ee).
