Ruthenium Catalyzed Selective Regio‐and‐Mono‐Allylation of Cyclic 1,3‐Diketones Using Allyl Alcohols as Substrates

Abstract

Abstract:The new ruthenium-sulfonate catalyst, rapidly and regioselectively mono-allylates dimedone to the branched products using substituted allyl alcohols as substrates, without acid, base or other additives, under relatively mild conditions. We consider the ruthenium sulfonate to be a "green" alternative in that it uses allyl alcohols as substrate, (rather than carbonates, acetates, etc.) and therefore does not waste the leaving group. The catalyst induces rapid double allylation of various 1,3-diketones in high yield using allylic alcohol.

Direct Nucleophilic SN1‐Type Reactions of Alcohols

“…Pregosin also reported the use of these interesting ruthenium complexes in other catalytic reactions. [106] Lau and co-workers published an interesting report on the effective role played by Lewis acids in S N 1-type reactions. The perchlorate salt of the dicationic bipy-ruthenium complex cis-[Ru(6,6Ј-Cl 2 bipy)(…”

Transition metal catalyzed nucleophilic allylic substitution: activation of allylic alcohols via π-allylic species

“…Thus, starting from aromatic allylic alcohol, the regioselective monoallylation of dimedone was achieved in high yield at room temperature in acetonitrile (Scheme 47). 71 Double allylation was not observed starting from these bulky allylic alcohols, however, once one allylic substituent was introduced, it was possible to perform a second allylation with the unsubstituted allyl alcohol leading to unsymmetrical diallylated products. Similarly, it was possible to monoallylate a cyclic 2-substituted 1,3-diketone with allyl alcohol.…”

“…One pot double allylation with allyl alcohol was also possible at 50 1C in acetonitrile from a variety of cyclic diketones (Scheme 48). 71 The ruthenium(IV) complex 9 containing a chelating phosphinesulfonate ligand has been recently prepared. 72 It showed a remarkable catalytic activity in allylic substitution of indole starting from allylic alcohols.…”

Preparation and Structural Characterization of [CpRu(1,10‐phenanthroline)(CH3CN)][X] and Precursor Complexes (X=PF6, BArF, TRISPHAT‐N)

“…In fact, the CpRu fragment, and its Cp*Ru analogue, are recognized as effective catalysts for the promotion of many versatile synthetic transformations [4,5,8–12] . Of importance for the current study, combinations of [CpRu] and nitrogen‐based ligands [1,3,13,14] such as diimines [15–26] were also found to catalyze original processes [7,27,28] . For example, [CpRu(CH 3 CN) 3 ][PF 6 ] and pyridine‐imine/pyridine‐oxazoline ligands are effective catalysts in enantioselective decarboxylative rearrangements of allylic β‐ketoesters and carbonates [26,29–32] .…”

“…[4,5,[8][9][10][11][12] Of importance for the current study, combinations of [CpRu] and nitrogenbased ligands [1,3,13,14] such as diimines [15][16][17][18][19][20][21][22][23][24][25][26] were also found to catalyze original processes. [7,27,28] For example, [CpRu(CH 3 CN) 3 ][PF 6 ] and pyridine-imine/pyridine-oxazoline ligands are effective catalysts in enantioselective decarboxylative rearrangements of allylic β-ketoesters and carbonates. [26,[29][30][31][32] Kitamura successfully applied enantiopure dipyrroloimidazole ligands and [CpRu] in enantioselective dehydrative C-, N-, and Oallylation.…”