Haughey, Johannes C. Arjunreddy Mallampudi, Debendra K. In this chapter the reader quickly becomes acquainted with a plethora of natural compounds having diverse pharmacological properties that can be accessed easily by RCM. DFT calculations show that this broadening is due to an interaction between these methylene groups and the residual surface aluminum groups. Weiss et al. Indeed, the coordination environment of 22is very similar to that of the trisoxo alkyl dinuclear complex [O WONp3 2] which is stable toward excess water. Armstrong, Madison B. Wedler, Paul Wendelboe, Christopher G. Casey et al. Buchmeiser et al. When the support has been previously functionalized, the bonding can be made via other atoms such as P, N, Si, etc. The characterization of the grafted materials by infrared spectroscopy, chemical analysis, and solid-state NMR shows that the presence of these sterically encumbered ligands leads to a nonselective grafting reaction.
The reaction products, decene and methyl decenoate, are important intermediates in the chemical industry and are used for the preparation of polyolefins, surfactants, and lubricating compounds. These results are in agreement with the UV-visible results. The catalyst containing 4 wt.
The mechanism of formation of this surface species was elucidated by use of DFT calculations. This example shows that the support can have a nonnegligible effect on the catalysis.
The first chapters report on RCM as the first, and still most widely used, type of metathesis reaction for natural product synthesis.
Cross-metathesis of ethylene and methyl oleate. Journal of the American Chemical Society33 The bis-siloxy oxo alkylidene tungsten complex 14 has been described recently.
Hanson University of Kansas, USA demonstrate the role played by RCM in the construction of sultone and phosphate heterocycles, thus providing an effective method in which both sulfur and phosphorus serve as temporary tethers to mediate several selective transformations.
Mechanism of the olefin metathesis reaction. Addition of a Lewis acid such as B C6F5 3 leads to a considerable increase of both the activity and the selectivity.
Olefin metathesis functional group tolerance
Raffael Schrof, Karl-Heinz Altmann. Organic Letters , 20 12 , However, further developments in catalyst design are needed in order to improve understanding and broaden the applicability of the RCAM strategy for natural product synthesis. Hamaker, John R. Additionally, data on the related carbonyl olefination cyclisation using a stoichiometric titanium reagent are included. Organic Letters , 20 23 , Examples of O—SiR2—O tethered substrates symmetrical and unsymmetrical silaketals , O—SiR2—C tethered substrates allyl- and vinylsiloxanes , and enyne and dienyne TST-RCM, are given to illustrate the versatility of this strategy for the synthesis of challenging structures encountered in total synthesis protocols. Accounts of Chemical Research , 52 2 ,
The mechanism of this reaction passes probably via the same ethyl ethylidene oxo tungsten complex than above as ethane is also detected at the first stages of the reaction. Meek and Adil R.
based on 42 review