نتایج جستجو برای: metathesis

تعداد نتایج: 2718  

2015
Lorenzo Piola Fady Nahra Steven P Nolan

Since the discovery and now widespread use of olefin metathesis, the evolution of metathesis catalysts towards air stability has become an area of significant interest. In this fascinating area of study, beginning with early systems making use of high oxidation state early transition metal centers that required strict exclusion of water and air, advances have been made to render catalysts more ...

2016
Jakkrit Suriboot Hassan S. Bazzi David E. Bergbreiter

Ruthenium and molybdenum catalysts are widely used in synthesis of both small molecules and macromolecules. While major developments have led to new increasingly active catalysts that have high functional group compatibility and stereoselectivity, catalyst/product separation, catalyst recycling, and/or catalyst residue/product separation remain an issue in some applications of these catalysts. ...

Journal: :Nature Chemistry 2016

Journal: :Journal of Japan Oil Chemists' Society 1975

Journal: :Journal of the American Chemical Society 2013
Raymond A Weitekamp Harry A Atwater Robert H Grubbs

Patterning functional materials is a central challenge across many fields of science. The ability to lithographically fabricate micro- and nanostructures has been one of the most impactful technological breakthroughs of the last century. In part due to the complexity of the chemical processes in photoresists, there is a limited variety of materials that can currently be patterned by photolithog...

2013
Paul De Palma Sara Ganzerli Shannon Overbay George Luger Kim Glaspey

It is now well understood that language use shapes the acoustic delivery of phonological patterns. One common example of this type of language change-under-use is metathesis, which is the reversal of the expected linear ordering of sounds. The gradual transformation of the Spanish word chipotle to chipolte in the United States is an example of metathetic change. The Genetic Algorithm (GA) is an...

Journal: :The Journal of organic chemistry 2005
Francisco Sarabia Antonio Sánchez-Ruiz

[Reaction: see text]. The total synthesis of the natural product Bengamide E, one of the members of a new class of antitumor natural products of marine origin, is reported based on a convergent and flexible synthetic route featuring an oxirane ring-opening reaction and an olefin cross metathesis. In a similar way, analogues structurally modified at C-2 and at the terminal vinyl positions were p...

Journal: :Chemical communications 2005
Nourdin Ghalit Johan Kemmink Hans W Hilbers Cees Versluis Dirk T S Rijkers Rob M J Liskamp

This paper describes two approaches for the synthesis of a crossed alkene-bridged mimic of the thioether ring system of the nisin Z DE-fragment. The first approach comprised the stepwise total synthesis featuring a cross metathesis and a macrolactamization on a solid support followed by a ring-closing metathesis in solution. Via this route the title compound was obtained in an overall yield of ...

2014
Simone Manzini José A. Fernández-Salas Steven P. Nolan

One of the most important challenges in catalyst design is the synthesis of stable promoters without compromising their activity. For this reason, it is important to understand the factors leading to decomposition of such catalysts, especially if side-products negatively affect the activity and selectivity of the starting complex. In this context, the understanding of termination and decomposit...

Journal: :Journal of Japan Oil Chemists' Society 1976

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