875304-23-7Relevant academic research and scientific papers
Enantio-and diastereoselective nitro-Mannich reactions with in situ generated N-Boc-imines catalyzed by a bifunctional thiourea-guanidine catalyst
Huang, Wei,Peng, Cheng,Guo, Li,Hu, Rong,Han, Bo
supporting information; experimental part, p. 2981 - 2984 (2012/01/06)
The asymmetric nitro-Mannich reactions of nitroalkanes and in situ generated N-Boc-imines were achieved with a new type of thiourea-guanidine bifunctional organocatalyst. The novel transformations exhibited good diastereoselectivities, and the adducts bearing adjacent chiral centers were generally obtained in moderate to high enantioselectivities (up to 94% ee). This reaction provides a concise and alternative route converting readily accessible and stable N-carbamate amido sulfones into optically active 1,2-diamino compounds. Georg Thieme Verlag Stuttgart · New York.
Bifunctional-thiourea-catalyzed diastereo- And enantioselective Aza-Henry reaction
Xu, Xuenong,Furukawa, Tomihiro,Okino, Tomotaka,Miyabe, Hideto,Takemoto, Yoshiji
, p. 466 - 476 (2008/09/20)
Bifunctional thiourea 1a catalyzes aza-Henry reaction of nitroalkanes with N-Boc-imines to give syn-β-nitroamines with good to high diastereo- and enantioselectivity. Apart from the catalyst, the reaction requires no additional reagents such as a Lewis acid or a Lewis base. The N-protecting groups of the imines have a determining effect on the chirality of the prod ucts, that is, the reaction of N-Bocimines gives R adducts as major products, whereas the same reaction of N-phosphonoylimines furnishes the corresponding S adducts. Various types of nitroalkanes bearing aryl, alcohol, ether, and ester groups can be used as nucleophiles, providing access to a wide range of useful chiral building blocks in good yield and high enantiomeric excess. Synthetic versatility of the addition products is demonstrated by the transformation to chiral piperidine derivatives such as CP-99,994.
