نتایج جستجو برای: stereoselective

تعداد نتایج: 4707  

Journal: :Molecules 2012
Koichi Tanaka

Stereoselective photodimerization of coumarin and its derivatives in supra-molecular systems is reviewed. The enantioselective photodimerization of coumarin and thiocoumarin in inclusion crystals with optically active host compounds is also described.

Journal: :Chemical communications 2006
P Andrew Evans Kwong Wah Lai Hai-Ren Zhang John C Huffman

The regioselective and enantiospecific rhodium-catalyzed allylic amination of secondary allylic carbonates with N3-benzoyl thymine in conjunction with a stereoselective free radical cyclization provides a convenient method for the construction of a new conformationally rigid nucleoside.

Journal: :Chemical communications 2004
Christophe Audouard Igor Barsukov John Fawcett Gerry A Griffith Jonathan M Percy Stéphane Pintat Clive A Smith

A (bromodifluoromethyl)alkyne has been deployed in a stereoselective route to difluorinated aldonic acid analogues, in which a Sharpless asymmetric dihydroxylation reaction and diastereoisomer separation set the stage for phenyl group oxidation.

Journal: :Organic letters 2002
Fabien P Boulineau Alexander Wei

[reaction: see text] 4-Deoxypentenosides, which are readily derived from D-sugars, resemble glycals in structure and reactivity and can undergo stereoselective epoxidation and S(N)2 nucleophilic addition to produce L-sugars in pyranosidic form.

2014
Arkady L. Krasovskiy Stephen Haley Karl Voigtritter Bruce H. Lipshutz

Stereoselective palladium-catalyzed Kumada-Corriu reactions of functionalized alkenyl halides and a variety of Grignard reagents, including those bearing β-hydrogen atoms and sensitive functional groups, can be carried out at room temperature using a new combination of reagents.

Journal: :Chemical communications 2003
Zhihui Shao Jingbo Chen Yongqiang Tu Liang Li Hongbin Zhang

Bromination of an isolated double bond followed by aminocyclization furnishes a highly stereoselective protocol for the intramolecular formation of pyrrolidine and piperidine ring containing subunits that are presented in numerous biologically active natural products.

Journal: :Chemical communications 2006
Christian Wolf Shuanglong Liu Brian C Reinhardt

A chiral 1,8-diacridylnaphthalene-derived fluorosensor exhibiting a C(2)-symmetric cleft designed for stereoselective interactions with hydrogen bond donors has been used for the determination of both concentration and enantiomeric composition of carboxylic acids and amino acid derivatives.

Journal: :Organic & biomolecular chemistry 2007
Yumiko Yamano Masayoshi Ito

The synthesis of capsanthin 1 and capsorubin 2 was accomplished via the C(15)-cyclopentyl ketone 6 prepared by Lewis acid-promoted regio- and stereoselective rearrangement of the epoxy dienal 5.

Journal: :Chemical communications 2013
Mercedes Amat Alexandre Pinto Rosa Griera Joan Bosch

A concise synthesis of the marine alkaloids (-)-lepadins A-C from a phenylglycinol-derived tricyclic lactam is reported. Key steps from the stereochemical standpoint involve stereoselective cyclocondensation, double bond hydrogenation, oxazolidine opening, hydroboration-oxidation, and Horner-Wadsworth-Emmons reactions.

2014
Valer Jeso Claudio Aquino Xiayun Cheng Haruki Mizoguchi Mika Nakashige Glenn C. Micalizio

Angularly substituted trans-fused hydroindanes are now accessible by the direct and convergent union of trimethylsilyl (TMS)-alkynes with 4-hydroxy-1,6-enynes by a process that forges three C-C bonds, one C-H bond, and two new stereocenters. The annulation is proposed to proceed by initial formation of a Ti-alkyne complex (with a TMS-alkyne) followed by regioselective alkoxide-directed coupling...

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