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.
Organocatalytic Asymmetric Mannich Reaction of 3-Hydroxyoxindoles/3-Aminooxindoles with in Situ Generated <i>N</i>-Boc-Protected Aldimines for the Synthesis of Vicinal Oxindole–Diamines/Amino Alcohols
A highly efficient asymmetricMannichreaction of 3-monosubstituted 3-aminooxindoles/3-hydroxyoxindoles with in situ generated N-Boc-protected aldimines catalyzed by the chiral bifunctional thiourea–tertiary amine catalyst has been developed. Under mild reaction conditions, a series of structurally diverse vicinal oxindole–diamines/amino alcohols were smoothly obtained in moderate to high yields (up
One-Pot Synthesis of α-Amino Acids from CO<sub>2</sub> Using a Bismetal Reagent with Si–B Bond
作者:Tsuyoshi Mita、Jianyang Chen、Masumi Sugawara、Yoshihiro Sato
DOI:10.1021/ol302952r
日期:2012.12.21
TsOH·H2O, precursors of N-Boc-imines can be converted into the corresponding α-aryl or α-alkenyl glycine derivatives under gaseous CO2 in moderate-to-high yields with a single operation. α-Isobutenyl glycine thus obtained can be further derivatized into various types of α-aminoacids including N-Boc-leucine, serine, and glycine derivatives in short steps.
catalytic enantio- and diastereoselective nitro-Mannichreaction of α-amido sulfones in the mixed solvent of toluene/H2O has been realized using a phase-transfer catalyst (PTC) derived from cinchona alkaloids and N-benzotriazole. It performed well over a wide range of substrates to give the desired products in good yields (up to 94%) with excellent enantioselectivities (up to 99% ee) and diastereoselectivities
使用衍生自金鸡纳生物碱和N-苯并三唑的相转移催化剂(PTC)实现了α-酰胺基砜在甲苯/ H 2 O混合溶剂中的催化对映体和非对映体的硝基曼尼希反应。它在各种底物上均表现良好,以高收率(最高94%)提供所需的产品,并具有出色的对映选择性(最高99%ee)和非对映选择性(最高99:1)。
Asymmetric Transfer Hydrogenation: Dynamic Kinetic Resolution of α-Amino Ketones
作者:Shweta K. Gediya、Guy J. Clarkson、Martin Wills
DOI:10.1021/acs.joc.0c01438
日期:2020.9.4
A series of α-amino ketones were reduced using asymmetrictransferhydrogenation (ATH) through a dynamic kinetic resolution (DKR). The protecting group was matched to the reducing agent, and following optimization, a series of substrates were investigated, giving products in high diastereoselectivity, over 99% ee in several cases and full conversion. The methodology was applied to the enantioselective