Bronsted acid-assisted chiral Lewis acid (BLA) was highly effective as a chiral catalyst for the enantioselective Diels−Alder reaction of both α-substituted and α-unsubstituted α,β-enals with various dienes. Hydroxy groups in opticallyactive binaphthol derivatives and boron reagents with electron-withdrawing substituents were used as Bronsted acids and Lewis acids, respectively. Intramolecular Bronsted
布朗斯台德酸辅助的手性路易斯酸 (BLA) 作为手性催化剂非常有效,可用于 α-取代和 α-未取代的 α,β-烯醛与各种二烯的对映选择性 Diels-Alder 反应。光学活性联萘酚衍生物中的羟基和具有吸电子取代基的硼试剂分别用作布朗斯台德酸和路易斯酸。手性 BLA 催化剂中的分子内布朗斯台德酸在加速 Diels-Alder 反应速率和产生高水平的对映选择性方面发挥了重要作用。特别是,由于手性 BLA 催化剂中羟基芳基在过渡态组装中的分子内氢键相互作用和有吸引力的 π-π 供体-受体相互作用,实现了优异的对映选择性。
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
Functionalization of BINOL-mono-PHOS achieved the Cu-catalyzed highly asymmetric conjugateaddition of organozincreagents to enones. The incorporation of a bulky hydroxy group at the 3′-position o...
Syntheses and Applications of 2-Phosphino-2‘-alkoxy-1,1‘-binaphthyl Ligands. Development of a Working Model for Asymmetric Induction in Hydrovinylation Reactions
作者:Biswajit Saha、T. V. RajanBabu
DOI:10.1021/jo062044h
日期:2007.3.1
Among the handful of monophosphine ligands that effect asymmetrichydrovinylation of vinylarenes, 2-diphenylphosphino-2‘-methoxy-1,1‘-binaphthyl (MOP) is among the most accessible. Addition of a methyl group at the 3‘-position of this ligand significantly improves the enantioselectivity of hydrovinylation of prototypical alkenes. Introduction of a chiral phospholane at the C2 position of this scaffolding
A new family of chiral chimeric photo-organocatalysts derived from phosphoric acid were synthesized and their spectroscopic and electrochemical properties were investigated. Then, the ability of these photo-activable molecules to catalyse an asymmetric tandem electrophilic β-amination of enecarbamates was evaluated.