Molybdenum and Tungsten Imido Alkylidene Complexes as Efficient Olefin‐Metathesis Catalysts

Abstract

Catalytic olefin metathesis has quickly emerged as one of the most often-used transformations in modern chemical synthesis. One class of catalysts that has led the way to this significant development are the high-oxidation-state alkylidene complexes of molybdenum. In this review key observations that resulted in the discovery and development of molybdenum- and tungsten-based metathesis catalysts are outlined. An account of the utility of molybdenum catalysts in the synthesis of biologically significant molecules is provided as well. Another focus of the review is the use of chiral molybdenum complexes for enantioselective synthesis. These highly efficient catalysts provide unique access to materials of exceptional enantiomeric purity and often without generating solvent waste.

First FT-Raman and 1H NMR comparative investigations in ring opening metathesis polymerization

“…Within this category olefin metathesis (mainly as ringclosing metathesis, cross-metathesis and ring-opening metathesis polymerization (ROMP)), has won a leading position owing to its success in yielding various natural products, specialty polymers, pharmaceuticals and otherwise hard-to-get organic compounds [1][2][3][4][5][6][7][8][9][10][11][12][13].…”

A Well-Defined, Silica-Supported Tungsten Imido Alkylidene Olefin Metathesis Catalyst

“…Moreover, they show that the surface complex has the usual pseudo-tetrahedral syn structure, the anti isomer lying 5.7 kcal mol -1 above. 5,25 The main difference between the calculated and experimental structures is the absence of a M···O(Si ) 2 . 26 We have also tested the catalyst (60mg, 3.5%) in a flow reactor at 30°C using propene (17 mL/min; 62 mol propene/mol W/min).…”

Where organometallics and dendrimers merge: the incorporation of organometallic species into dendritic molecules

“…Undoubtedly, olefin metathesis [56], with either ruthenium [57] or molybdenum [58] catalyst systems, is one of the more important reactions in polymer chemistry and natural product synthesis [59] and the ability to recover and reuse the catalysts would greatly impact the cost efficiency of these reactions. A simple dendrimer containing four active Ru sites was reported.…”