نتایج جستجو برای: vicinal dihalides
تعداد نتایج: 1696 فیلتر نتایج به سال:
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.
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...
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...
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...
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.
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...
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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