Tungsten-catalyzed allylic alkylations. New avenues for selectivity

Metal catalyzed allylic alkylation: its development in the Trost laboratories

“…It is also the stimulus to see what other metals can do in catalytic allylic alkylations. In our labs, we have explored a number of metals, including molybdenum, 145 tungsten, 146 and ruthenium. 147 These metal catalysts favor bond formation to the more substituted allyl terminus.…”

Syntheses, structures, and dynamic properties of M(CO)2(η3-C3H5)(en)(X) (M=Mo, W; X=Br, N3, CN) and [(en)(η3-C3H5)(CO)2M(μ-CN)M(CO)2(η3-C3H5)(en)]Br (M=Mo, W)

“…The group 6 metal allyl complexes M(CO) 2 (g 3 -C 3 H 5 )(L-L)(X) (M = Mo, W; L-L = bidentate ligand; X = anionic monodentate ligand) have been studied for more than four decades [1][2][3] due to their conformational and dynamic behavior [4][5][6] as well as their possible application in organic synthesis [7][8][9][10][11][12]. In general, when L-L is a rigid bidentate ligand the complex adopts conformation A (Scheme 1) in the solid state and displays non-fluxional behavior in solution [13,14].…”

Iridium-Catalyzed Allylic Substitution

“…Although this had been demonstrated for a large portion of the d-block before Takeuchi's work with iridium, most of the progress in this area was restricted to stabilized enolate nucleophiles. Prior to the initial disclosure of iridium-catalyzed allylic substitution, catalysts based on complexes of molybdenum [8][9][10][11][12][13][14][15][16][17][18], tungsten [19][20][21][22][23][24], iron [25][26][27][28], ruthenium [11,29,30], cobalt [27], rhodium [11,31], nickel [11,[32][33][34][35][36][37], and platinum [38] had all been shown to favor the formation of branched products from substrates that generate p-allyl intermediates that are unsubstituted at one terminus. In fact the widely recognized selectivity of palladium catalysts for the formation of linear products is actually an anomaly among transition metals.…”