ChemInform Abstract: Isomerization Reaction of Olefin Using RuClH(CO)(PPh₃)₃.

Abstract

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Isomerization of Allylbenzenes

“…van Otterlo and co-workers used the RuClH­(CO)­(PPh 3 ) 3 catalyst complex described earlier, with much success in their application of isomerization-RCM strategies toward the synthesis of various benzofused scaffolds. This particular approach was successfully used in the synthesis of oxygen- and nitrogen-containing benzofused heterocycles , as exemplified in Scheme in which the ruthenium hydride catalyst RuClH­(CO)­(PPh 3 ) 3 (see reference for earlier use of this catalyst as isomerization facilitator, and references cited therein) played an important role in the isomerization of substituted 2-allylphenols 571 to 572 , followed by an O -allylation to 573 and RCM with the second generation Grubbs catalyst GII , to afford the 2 H -chromenes 574 in mostly good yields. ,, It should be noted that this same catalyst has been used by other researchers on a similar substrate and with the same result, albeit in an unsuccessful attempt to achieve a ruthenium-mediated cyclization . Last, with respect to these classes of compounds, it should be noted that when van Otterlo and co-workers applied a double isomerization strategy on substrate 575 , followed by RCM with the Grubbs second generation catalyst GII , the 1 H -isochromene 576 was produced in a good yield of 83% over two steps…”

A Tandem Iridium-Catalyzed “Chain-Walking”/Cope Rearrangement Sequence

“…1−4 In contrast to directed remote functionalization (Scheme 1b), 5−9 metal-walk functionalization allows for the transformation of positions distal to the initiating site (Scheme 1c). 10−14 From the initial processes utilizing stoichiometric zirconium, 15−20 protocols relying on palladium, 13,21−25 ruthenium, 26,27 nickel, 28,29 or cobalt 30,31 catalysis have been developed and applied in various C−C-and C−X-bond forming processes, respectively. 12−14 Continuing our efforts to combine transition-metal-catalyzed chain-walking processes with subsequent remote functionalization, 13,19,20,25 we decided to explore the possibility to intercept an intermediately formed olefin in a rearrangement process.…”