24486-16-6Relevant academic research and scientific papers
Group-Assisted Purification Chemistry for Asymmetric Mannich-type Reaction of Chiral N-Phosphonyl Imines with Azlactones Leading to Syntheses of α-Quaternary α,β-Diamino Acid Derivatives ?
Zhang, Haowei,Yang, Zhen,Zhao, Brian Nlong,Li, Guigen
, p. 644 - 655 (2018/01/27)
An asymmetric Mannich-type reaction between chiral N-phosphonyl imines and azlactones [oxazol-5(4H)-ones] has been established under convenient conditions at room temperature. The reaction was performed without using any bases, additives, or catalysts to achieve up to excellent chemical yields and diastereoselectivity for 32 examples. The α-quaternary syn-α,β-diamino acid products were purified simply by washing the crude mixtures with cosolvents, following the group-assisted purification chemistry/technology, without involving traditional chromatography or recrystallization methods. The auxiliary can be readily removed and recycled for reuse. The absolute configuration was unambiguously assigned by X-ray structural analysis.
Organocatalytic oxyamination of azlactones: Kinetic resolution of oxaziridines and asymmetric synthesis of oxazolin-4-ones
Dong, Shunxi,Liu, Xiaohua,Zhu, Yin,He, Peng,Lin, Lili,Feng, Xiaoming
supporting information, p. 10026 - 10029 (2013/07/26)
The first example of oxyamination of azlactones with oxaziridines was realized using a chiral bisguanidinium salt. Efficient catalytic asymmetric oxyamination and kinetic resolution of oxaziridines occurred simultaneously. Various chiral oxazolin-4-one derivatives with potential biological activity were obtained (up to 92% ee). Meanwhile, a series of optically pure oxaziridines were recovered with up to 99% ee and successfully used in the asymmetric oxyamination of 3-methyl-1H-indole and styrene. The triple stereodifferentiation process was also studied via control experiments.
Asymmetric synthesis of 3, 4-diaminochroman-2-ones promoted by guanidine and bisguanidium salt
Dong, Shunxi,Liu, Xiaohua,Zhang, Yulong,Lin, Lili,Feng, Xiaoming
supporting information; experimental part, p. 5060 - 5063 (2011/12/05)
A highly enantioselective synthesis of 3,4-diaminochroman-2-ones has been realized via the domino reaction of o-hydroxy aromatic aldimines and azlactones. Notably, a cis-product was obtained as the major product by the use of guanidine 2a whereas a trans-product was the major product with bisguanidium salt 3·HBArF 4. In two cases, various substituted 3,4-dihydrocoumarins were obtained with high yields (up to 99%) as well as excellent enantioselectivities (up to 99% ee) and diastereoselectivities (up to >99:1 cis:trans and 98:2 trans:cis, respectively) under mild reaction conditions.
