Titanium catalysts enynes

Subsequently, direct incorporation of GO by titanocene(ii) catalyst, Gp2Ti(GO)2, under a GO atmosphere was reported.This catalytic system showed substantially higher TON and broader functional group compatibility. However, this catalyst fails to react with sterically hindered olefins and alkynes. In a recent contribution from the same group, a series of aryloxide titanium complexes 22 (figure 4) are prepared and shown to promote PKR with some sterically hindered enynes." ... 

A practical titanium-catalyzed synthesis of bicyclic cyclopentenones and allylic amines is described. The process converts enyne substrates to iminocyclopentenes using 10 mol% of the air- and moisture-stable pre-catalyst Cp2TiCl2 in the presence of LiBu" and triethylsilyl cyanide.1... 

Acylations have generally been carried out using aluminum chloride as catalyst, although on occasions no catalyst was required." Titanium tetrachloride proved superior to aluminum, tin(IV) and zinc chlorides in reactions of 4-substituted-l-trimethylsilylbuta-l,3-diynes and the derived (Z)-enynes." The most frequently used solvents are chlorinated hydrocarbons," - " in preference to carbon disulfide and nitrobenzene." ... 

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