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。
Palladium-Catalyzed Benzylic Addition of 2-Methyl Azaarenes to <i>N</i>-Sulfonyl Aldimines via C−H Bond Activation
generation of amines by palladium-catalyzed nucleophilic benzylic addition of 2-methyl-substituted azaarenes to N-sulfonyl aldimines under neutral conditions via C-H bondactivation has been developed. This reaction represents a very efficient methodology for the synthesis of heterocycle-containing amines and thus opens a new way to access amines through C-H bondactivation.
Iron-Catalyzed Direct Alkenylation of 2-Substituted Azaarenes with <i>N</i>-Sulfonyl Aldimines via C–H Bond Activation
作者:Bo Qian、Pan Xie、Yinjun Xie、Hanmin Huang
DOI:10.1021/ol200684b
日期:2011.5.20
A novel iron-catalyzed alkenylation of 2-substituted azaarenes through sp3 C–Hbondactivation has been developed. A favorable E2-elimination is proposed as a key step to cleavage of C–H and C–N bonds for the construction of a C═C bond in high stereoselectivity. This transformation represents an efficient way to synthesize 2-alkenylated azaarenes from simple starting materials.
Catalytic, Asymmetric Aza-Baylis-Hillman Reaction ofN-Sulfonated Imines with Activated Olefins by Quinidine-Derived Chiral Amines
作者:Min Shi、Yong-Mei Xu、Yong-Ling Shi
DOI:10.1002/chem.200400872
日期:2005.3.4
such as methyl vinyl ketone (MVK), ethyl vinyl ketone (EVK), acrolein, methylacrylate, phenyl acrylate, or alpha-naphthyl acrylate to give the corresponding adducts in moderate to good yields with good to high ee (up to 99 %) at -30 degrees C or 45 degrees C in various solvents, including DMF/MeCN (1:1, v/v). The first such reaction of 1 with the simplest Michael acceptor MVK and methylacrylate has been
Chiral Phosphine Lewis Bases Catalyzed Asymmetric aza-Baylis−Hillman Reaction of N-Sulfonated Imines with Activated Olefins
作者:Min Shi、Lian-Hui Chen、Chao-Qun Li
DOI:10.1021/ja0447255
日期:2005.3.1
In the aza-Baylis-Hillman reaction of N-sulfonated imines (N-arylmethylidene-4-methylbenzenesulfonamides and others) with methyl vinyl ketone, ethyl vinyl ketone, and acrolein, we found that, in the presence of a catalytic amount of chiralphosphineLewis base such as (R)-2'-diphenylphosphanyl-[1,1']binaphthalenyl-2-ol LB1 (10 mol %) and molecular sieve 4A, the corresponding aza-Baylis-Hillman adducts