A novel [4+1] spiroannulation of o‐ & p‐bromophenols with α,β‐unsaturated imines has been developed for the direct synthesis of a new family of azaspirocyclic molecules. Notably, several other halophenols (X=Cl, I) were also applicable for this transformation. Moreover, a catalytic asymmetric version of the reaction was realized with 1‐bromo‐2‐naphthols by using a chiral ScIII/Py‐Box catalyst. Mechanistic
已经开发了一种新颖的[4 + 1]邻和对溴苯酚与α,β-不饱和亚胺螺环合成的方法,用于直接合成新的氮杂螺环分子家族。值得注意的是,其他几种卤代酚(X = Cl,I)也适用于该转化。此外,通过使用手性Sc III / Py-Box催化剂,使用1-溴-2-萘酚实现了反应的催化不对称形式。机理研究表明,该多米诺反应是通过苯酚衍生物在其卤代位置的亲电触发的脱芳香化作用进行的,然后通过基于自由基的S RN 1机理用N-亲核试剂进行卤素置换。
Aza-Morita–Baylis–Hillman reactions catalyzed by a cyclopropenylidene
作者:Xun Lu、Uwe Schneider
DOI:10.1039/c6cc06201f
日期:——
Catalysis using a bis(dialkylamino)cyclopropenylidene (BAC) has been developed, which relies on a formal umpolung activation of Michael acceptor pro-nucleophiles.
Branched Amine Synthesis via Aziridine or Azetidine Opening with Organotrifluoroborates by Cooperative Brønsted/Lewis Acid Catalysis: An Acid-Dependent Divergent Mechanism
作者:Truong N. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.8b01394
日期:2018.6.15
A practical catalytic method to synthesize β,β- and γ,γ-substituted amines by opening aziridines and azetidines, respectively, using alkenyl, alkynyl, or aryl/heteroaryl trifluoroborate salts is described. This reaction features simple open-flask reaction conditions, the use of transition-metal-free catalysis, complete regioselectivity, and high diastereoselectivity. Preliminary mechanistic studies
A palladium-catalyzed intramolecular amination of alkenes with retention of olefin functionalization was achieved under mild reaction conditions. In the presence of palladium catalyst, the tosyl-protected amine can directly couple with a double bond to provide versatile dihydropyrrole derivatives in moderate to excellent yields.
Expanding the Utility of Brønsted Base Catalysis: Biomimetic Enantioselective Decarboxylative Reactions
作者:Yuanhang Pan、Choon Wee Kee、Zhiyong Jiang、Ting Ma、Yujun Zhao、Yuanyong Yang、Hansong Xue、Choon-Hong Tan
DOI:10.1002/chem.201100687
日期:2011.7.18
of simple esters, the use of them as nucleophiles in directasymmetric transformations is a long‐standing challenge in synthetic organic chemistry. Nature approaches this difficulty through a decarboxylative mechanism, which is used for polyketide synthesis. Inspired by nature, we report guanidine‐catalyzed biomimetic decarboxylative CC and CN bond‐formation reactions. These highly enantioselective