Highly Efficient Asymmetric Mannich Reaction of Dialkyl α-Diazomethylphosphonates with <i>N</i>-Carbamoyl Imines Catalyzed by Chiral Brønsted Acids
作者:Hui Zhang、Xiaojing Wen、Lihua Gan、Yungui Peng
DOI:10.1021/ol300664d
日期:2012.4.20
An efficient method involving the first use of chiral phosphoric acids as catalysts in the asymmetricMannichreaction of dialkyl diazomethylphosphonates and N-carbamoyl imines is developed. With only 0.1 mol % catalyst 1f, the reaction proceeded smoothly and produced the corresponding β-amino-α-diazophosphonate with up to 97% yield and >99% ee.
Strategy for Stereoselective Metal-free α-Functionalization of 2-Azaaryl Acetates with <i>N</i>
-Boc Imines
作者:Iñaki Bastida、Marcos San Segundo、Rosa López、Claudio Palomo
DOI:10.1002/chem.201703748
日期:2017.9.27
We report the first diastereo‐ and enantioselective formal Mannich reaction of 2‐pyridyl acetates which gives rise to α‐ and β‐functionalized 2‐substituted pyridines. Key for success is the previous azaarene N‐oxide formation enabling α‐carbon deprotonation by a mild bifunctional Brønsted base and subsequent reaction with N‐Boc imines under almost perfect stereocontrol.
dehalogenation and thus largely neglected as enolate precursors in catalytic enantioselective C-C bond-forming reactions. By merging the increased stability of the α-C-halogen bond of amides and the direct enolization methodology of the designed amide, we explored a direct catalytic asymmetric Mannich-typereaction of α-halo 7-azaindoline amides with N-carbamoyl imines. All α-halo substituents, α-F, -Cl, -Br, -I
α-卤代羰基化合物易于脱卤,因此在催化对映选择性 CC 键形成反应中作为烯醇前体在很大程度上被忽视。通过将酰胺的 α-C-卤素键的稳定性提高和设计酰胺的直接烯醇化方法相结合,我们探索了 α-卤代 7-氮杂二氢吲哚酰胺与 N-氨基甲酰基亚胺的直接催化不对称曼尼希型反应。所有 α-卤素取代基,α-F、-Cl、-Br、-I 酰胺都可以耐受,以高度立体选择性的方式提供曼尼希加合物,而不会发生不希望的脱卤。非对映选择性根据芳族亚胺的取代模式发生有趣的变化,这归因于基于开放过渡态模型的立体化学分化。
Enantio- and diastereoselective double Mannich reaction of malononitrile with <i>N</i>-Boc imines using quinine-derived bifunctional organoiodine catalyst
作者:Satoru Kuwano、Eri Ogino、Takayoshi Arai
DOI:10.1039/d1ob00796c
日期:——
asymmetric double Mannichreaction of malononitrile with N-Boc and N-Cbz imines to afford 1,3-diamines in excellent yields with high enantio- and diastereoselectivities. With 2.2 equiv. of a single imine electrophile, symmetrical 1,3-diamines were obtained, whereas, with two different imine partners, unsymmetrically substituted 1,3-diamine was obtained. The monohydration of the double Mannich product was