نتایج جستجو برای: vicinal dihalides

تعداد نتایج: 1696  

Journal: :Organic letters 2015
Sedef Karabiyikoglu Robert G Iafe Craig A Merlic

A new strategy to access macrocyclic enynes was developed. To block undesired ene-yne cyclization pathways, alkynes were protected via bromination and the resultant acyclic vic-(E)-dibromotrienes participated in selective ene-ene ring closing metathesis reactions. Zinc-promoted deprotection of (E)-dibromodienes provided macrocyclic enynes in high yields.

Journal: :Chemical science 2017
Haoyu Li Cuicui Shan Chen-Ho Tung Zhenghu Xu

Regioselective difunctionalization of alkenes has attracted significant attention from synthetic chemists and has the advantage of introducing diverse functional groups into vicinal carbons of common alkene moieties in a single operation. Herein, we report an unprecedented intermolecular atom transfer thiosulfonylation reaction of alkenes by combining gold catalysis and visible-light photoredox...

Journal: :Journal of medicinal chemistry 2005
Gian Cesare Tron Francesca Pagliai Erika Del Grosso Armando A Genazzani Giovanni Sorba

Combretastatin A-4 is an antitumoral and antitubulin agent that is active only in its cis configuration. In the present manuscript, we have synthesized cis-locked combretastatins embodying a furazan ring (combretafurazans). To achieve this, we have developed a new strategy that exploits the dehydration of vicinal dioximes using the Mitsunobu reaction. Among the advantages of following such a st...

Journal: :Canadian Journal of Chemistry 1982

Journal: :Chemical science 2017
Luis Bering Andrey P Antonchick

A transition-metal-free cis-dihydroxylation of saturated hydrocarbons under ambient reaction conditions has been developed. The described approach allows a direct and selective synthesis of vicinal diols. The new reaction thereby proceeds via radical iodination and a sequence of oxidation steps. A broad scope of one-pot dual C(sp3)-H bond functionalization for the selective synthesis of vicinal...

1999
Andreas Scheurer Paul Mosset Rolf W. Saalfrank

C2-symmetric vicinal diamines 3b–f, derived from L-tartaric acid, with increasingly bulky terminal ether functionalities were prepared using two distinct sequences. Diamines 3b,c were obtained from the corresponding vicinal diols 4b,c, while diamines 3d–f were generated from dihydroxydiazide 7 via deprotection–reprotection strategies. © 1999 Elsevier Science Ltd. All rights reserved.

Journal: :Organic & biomolecular chemistry 2012
Oskari K Karjalainen Ari M P Koskinen

The vicinal amino alcohol is a common motif in natural products and pharmaceuticals. Amino acids constitute a natural, inexpensive, and enantiopure choice of starting material for the synthesis of such functionalities. However, the matters concerning diastereoselectivity are not obvious. This Perspective takes a look in the field of diastereoselective synthesis of vicinal amino alcohols startin...

Journal: :The Journal of Chemical Physics 1959

Journal: :Science 2005
J N Crain D T Pierce

End states--the zero-dimensional analogs of the two-dimensional states that occur at a crystal surface--were observed at the ends of one-dimensional atom chains that were self-assembled by depositing gold on the vicinal Si(553) surface. Scanning tunneling spectroscopy measurements of the differential conductance along the chains revealed quantized states in isolated segments with differentiated...

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