Diastereoselective preparation of novel tetrahydrooxazinones via heterocycloaddition of N-Boc, O-Me-acetals
作者:Patricia Gizecki、Ramzi Ait Youcef、Céline Poulard、Robert Dhal、Gilles Dujardin
DOI:10.1016/j.tetlet.2004.10.154
日期:2004.12
Under Lewis acid conditions, reaction of N-Boc, O-Me acetals with the (R)-(+)-O-vinyl-pantolactone does not lead to the expected dihydrooxazine, but to the corresponding tetrahydrooxazinone, as a result of the loss of the t-Bu group. A diastereoselective and asymmetrical way to these new heterocyclic compounds is described, together with the first evidence of their ability to undergo N-acylation.
Chiral ureas and thioureas supported on polystyrene for enantioselective aza-Henry reactions under solvent-free conditions
作者:Rafael Pedrosa、José M. Andrés、Deisy P. Ávila、Miriam Ceballos、Rodrigo Pindado
DOI:10.1039/c4gc02474e
日期:——
Chiral recoverable supported bifunctional ureas or thioureas promote highly enantioselective aza-Henry reactions under solvent-free conditions.
手性可回收支持的双功能脲或硫脲在无溶剂条件下促进高对映选择性的无溶剂条件下的氮杂-Henry反应。
Asymmetric Aza-Morita-Baylis-Hillman Reactions of Alkyl Vinyl Ketones with N-Protected Imines or In Situ Generated N-Protected Imines
作者:Xiao-Yang Guan、Yin Wei、Min Shi
DOI:10.1002/ejoc.201000496
日期:2010.7
DABCO-catalyzed aza-MBH reactions of N-Boc imines with MVK and EVK have been thoroughly investigated in the paper. The asymmetric version of this aza-MBH reaction was also systematically investigated by using a chiral amine or a chiral phosphane catalyst. It was found that most of the N-protected imines are suitable substrates under the mild reaction conditions and are able to give the corresponding
DABCO 催化的 N-Boc 亚胺与 MVK 和 EVK 的 aza-MBH 反应已在论文中进行了彻底的研究。还通过使用手性胺或手性磷烷催化剂系统地研究了这种 aza-MBH 反应的不对称形式。发现大多数 N 保护的亚胺在温和的反应条件下是合适的底物,并且能够以中等产率和高 ee 值得到相应的加合物。TQO-或LB1-催化的N-保护的α-酰氨基烷基苯砜或α-酰氨基烷基对甲苯基砜与MVK的氮杂-MBH反应可以很好地进行,这为获得高对映选择性氮杂-MBH加合物提供了一种简便直接的途径.
Novel bifunctional thiourea–ammonium salt catalysts derived from amino acids: application to highly enantio- and diastereoselective aza-Henry reaction
作者:Hong-Yu Wang、Zhuo Chai、Gang Zhao
DOI:10.1016/j.tet.2013.04.079
日期:2013.6
development of new efficient and easily accessible catalysts has been one of the focuses in asymmetric phase-transfer catalysis. In this paper, a novel class of chiral bifunctional thiourea–ammonium phase-transfercatalysts were synthesized from commercially available α-amino acids. The structural modularity of these catalysts permits facile tunings to achieve optimum results, which was demonstrated
Catalytic Asymmetric Synthesis of Trisubstituted Aziridines
作者:Li Huang、William D. Wulff
DOI:10.1021/ja203754p
日期:2011.6.15
is described which provides for the direct asymmetric catalytic synthesis of trisubstituted aziridines fromimines and diazo compounds. While unactivated imines were not reactive to α-diazo carbonyl compounds in which the diazo carbon was disubstituted, N-Boc imines react with both α-diazo esters and α-diazo-N-acyloxazolidinones to give trisubstituted aziridines with excellent diastereo- and enantioselectivities