Iron Catalyzed Highly Enantioselective Epoxidation of Cyclic Aliphatic Enones with Aqueous H<sub>2</sub>O<sub>2</sub>
作者:Olaf Cussó、Marco Cianfanelli、Xavi Ribas、Robertus J. M. Klein Gebbink、Miquel Costas
DOI:10.1021/jacs.5b12681
日期:2016.3.2
An iron complex with a C1-symmetric tetradentate N-based ligand catalyzes the asymmetric epoxidation of cyclic enones and cyclohexene ketones with aqueous hydrogen peroxide, providing the corresponding epoxides in good to excellent yields and enantioselectivities (up to 99% yield, and 95% ee), under mild conditions and in short reaction times. Evidence is provided that reactions involve an electrophilic
具有 C1 对称四齿 N 基配体的铁配合物催化环烯酮和环己烯酮与过氧化氢水溶液的不对称环氧化反应,提供相应的环氧化物,产率和对映选择性都很好(高达 99% 和 95% ee ),条件温和,反应时间短。有证据表明反应涉及亲电氧化剂,并且该元素用于对包含两个烯烃位点的烯酮进行位点选择性环氧化。
Cross-conjugated Trienamine Catalysis with α′-Alkylidene 2-Cyclohexenones: Application in β,γ-Regioselective Aza-Diels-Alder Reaction
Endo‐type cross‐conjugated trienamines between highly congested α′‐alkylidene 2‐cyclohexenones and a chiral primary amine catalyst serve as HOMO‐raised dienophiles in inverse‐electron‐demand aza‐Diels–Alder cycloadditions with a number of 1‐azadiene substrates. The reactions exhibit exclusive β,γ‐regioselectivity, and multifunctional products with high molecular complexity are efficiently constructed
Double Thiol-Chiral Brønsted Base Catalysis: Asymmetric Cross Rauhut–Currier Reaction and Sequential [4 + 2] Annulation for Assembly of Different Activated Olefins
the intermolecular cross Rauhut-Currierreaction of 2-cyclopentenone and isatin-based alkylidene malononitriles. The resulting chiral adducts were sequentially assembled with diverse electron-deficient olefins to furnish highly enantioenriched cyclohexane derivatives (up to 96:4 er, >19:1 dr). A similar catalytic system of 2-mercaptobenzoic acid and quinine was further developed for the reaction of
stereocontrolled [8+2] and [6+4] cycloadditions have been largely neglected for the past 50 years. Here we demonstrate a cross-dienamine activation of 2-cyclopentenone and the unprecedented endocyclic linear-dienamine activation of 2-cyclohexenones and 2-cycloheptenones. These dienamine intermediates undergo aminocatalytic stereoselective [8+2], [6+4] and formal [4+2] cycloadditions with various heptafulvenes
An asymmetric intermolecular Rauhut‐Currier reaction of α′‐alkylidene2‐cyclohexenones and (7‐aza)isatinylidene malononitriles is realized under the double activation catalysis of natural quinine and 2‐mercaptobenzoic acid, finally affording formal 3‐arylated spiro (7‐aza)oxindole derivatives in fair to excellent enantioselectivity after a tandem cyclization/aromatization process (up to 96% ee).