نتایج جستجو برای: aza wittig reaction

تعداد نتایج: 417079  

Journal: :The Journal of organic chemistry 2015
Keary M Engle Shao-Xiong Luo Robert H Grubbs

A three-step procedure has been developed for preparing ortho-alkoxybenzaldehydes from ortho-fluorobenzaldehydes that tolerates the use of sterically hindered sodium alkoxide nucleophiles. The protocol is modular and operationally convenient. The ortho-alkoxybenzaldehyde products can be converted in one additional step to ortho-alkoxystyrenes by a Wittig reaction. These styrenes are precursors ...

Journal: :Organic & biomolecular chemistry 2013
Zong-Ze Wu Yeong-Jiunn Jang Chia-Jui Lee Yen-Te Lee Wenwei Lin

An efficient and attractive synthesis of a series of novel poly-functionalized phosphorus zwitterions was achieved via three-component reactions of the corresponding functional nucleophiles, aldehydes, and Bu(3)P in the presence of acidic promoter. These polysubstituted zwitterions could regioselectively undergo further transformations to synthetically important furanonaphthoquinones and relate...

2017
Anna Kuźnik Roman Mazurkiewicz Beata Fryczkowska

The main synthetic routes towards vinylphosphonium salts and their wide applications in organic synthesis are discussed in this review. Particular attention is paid to the use of these compounds as building blocks for the synthesis of carbo- and heterocyclic systems after their prior transformation into the corresponding phosphorus ylides, followed by the intramolecular Wittig reaction with var...

Journal: :Organic & biomolecular chemistry 2014
Tony K M Shing Anthony W H Wong Huiyan Li Z F Liu Paul K S Chan

D-Ribose was converted into 3 novel carbobicyclic nucleosides bearing a bicyclo[4.3.0]nonane framework in 16-19 steps with 5-12% overall yields involving a Wittig olefination and an intramolecular Diels-Alder reaction as the key steps. The present synthesis also provides an efficient entry for chiral hydrindenones. The conformation studies of these carbanucleosides and their bio-evaluation as p...

Journal: :Carbohydrate research 2009
Jie Cheng Zhijie Fang Song Li Baohui Zheng Yuhua Jiang

An efficient three-step synthesis of d-mannoheptulose was successfully accomplished from 2,3,4,5,6-penta-O-benzyl-d-mannose. First, an olefinated sugar was prepared from 2,3,4,5,6-penta-O-benzyl-d-mannose via a Wittig reaction. Second, the key step, a 2-hydroxyoxirane product was unexpectedly obtained by oxidation of the olefinated sugar with potassium permanganate in aqueous acetone. Finally d...

2011
Ri-An Yan Xiao-Xia Li Guo-Qiang Li

The title compound, C(18)H(20)O(4), was synthesized by a Wittig-Horner reaction of diethyl 3,4-dimeth-oxy-benzyl-phosphate and 3,5-dimeth-oxy-benzaldehyde. In the crystal, the dihedral angle between the two aromatic rings is 2.47 (12)°. All the meth-oxy groups are almost coplanar with the aromatic ring to which they are attached [C-C-O-C torsion angles = -2.8 (3), -5.2 (4), -176.3 (2) and -178....

2009
Yu-Feng Li Fang-Fang Jian

The title compound, C(28)H(22)O(6)S(2)·2C(6)H(13)N·2H(2)O, was prepared by the reaction of a Wittig reagent and 2-formyl-benzene-sulfonic acid. The main molecule lies about an inversion centre at the midpoint of the C-C bond between the inner benzene rings. The mol-ecular conformation is stabilized by intramolecular hydrogen bonds. The crystal structure is further stabilized by O-H⋯O and N-H⋯O ...

Journal: :The Journal of organic chemistry 2001
U Bhatt M Christmann M Quitschalle E Claus M Kalesse

The first total synthesis of ratjadone was achieved using a highly convergent approach joining three subunits together with a Wittig olefination and a selective Heck reaction as the pivotal steps. Besides establishing a robust and reliable route for the synthesis of this orphan ligand, the configuration of unknown stereocenters could also be determined. This synthesis not only provides an addit...

2014
Jie Zhao Jianchao Yuan Weibing Xu Jingjing Chen Yanqiong Mu

In the title compound, C36H36N2, a product of the condensation reaction of 2,3-dimethyl-6-phenyl-vinyl-benzenamine and 2,3-butane-dione, the complete mol-ecule is generated by the application of an inversion centre. The central C-C bond in the 1,4-di-aza-butadiene fragment is trans-configured and situated about the inversion center. The dihedral angle between the ring attached to N and the 1,4-...

2013
Aleksey I Gerasyuto Zhi-Xiong Ma Grant S Buchanan Richard P Hsung

A successful enone version of an intramolecular aza-[3 + 3] annulation reaction is described here. Use of piperidinium trifluoroacetate salt as the catalyst and toluene as the solvent appears to be critical for a successful annulation. We also demonstrated for the first time that microwave irradiation can accelerate aza-[3 + 3] annulation reactions. An attempt to expand the scope of the enone a...

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید