Divergent Approach to a Family of Tyrosine-Derived Ru–Alkylidene Olefin Metathesis Catalysts

Abstract

A simple and generic approach to access a new family of Ru-alkylidene olefin metathesis catalysts with specialized properties is reported. This strategy utilizes a late stage, utilitarian Hoveyda-type ligand derived from tyrosine, which can be accessed via a multigram-scale synthesis. Further functionalization allows the catalyst properties to be tuned, giving access to modified second-generation Hoveyda-Grubbs-type catalysts. This divergent synthetic approach can be used to access solid-supported catalysts and catalysts that function under solvent-free and aqueous conditions.

Acid‐Assisted Direct Olefin Metathesis of Unprotected Carbohydrates in Water

“…To address this limitation, several strategies to enable olefin metathesis in aqueous media have been proposed,i ncluding the use of biphasic systems, [32] immobilized catalysts, [33,34] nanoreactors and micellar catalysis, [35][36][37][38][39] artificial metallo-enzymes, [40] as well as modificationso ft he catalysts or the reaction conditions to increase the reactivity. [41][42][43][44][45][46][47][48][49][50] Unfortunately,m any of these systems are either incompatiblew ith water-soluble substrates or have av ery narrow substrate scope. [31,51,52] The olefin metathesis reactionhas nevertheless been applied to carbohydrates to somee xtent, [53] generally by using protected structures in organic solvents.…”

“…The majority of biologically interesting structures, such as unprotected peptides and carbohydrates, have therefore been largely incompatible with the reactions. To address this limitation, several strategies to enable olefin metathesis in aqueous media have been proposed, including the use of biphasic systems, immobilized catalysts, nanoreactors and micellar catalysis, artificial metallo‐enzymes, as well as modifications of the catalysts or the reaction conditions to increase the reactivity . Unfortunately, many of these systems are either incompatible with water‐soluble substrates or have a very narrow substrate scope …”

Synthesis and characterization of versatile amphiphilic dendrimers peripherally decorated with positively charged amino acids

“…The esterification reactions of 1 and 2 were performed according to a slightly modified literature protocol . The acyl chloride 3 , previously prepared from stearic acid following a reported procedure (Experimental procedure S1 in the supporting information), was reacted with 1 or 2 affording in both cases very complex crudes (File S1, Experimental procedure S2 and S5).…”

“…Compounds 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13b , 13c and 32 were prepared according to reported procedures (Experimental procedure S1–S11 and S14, Figs S1–S3, Table S1 in the supporting information). Dendrimers 14 – 23 were prepared by applying routine organic transformations whose experimental details are available in the supporting information (Experimental procedure S12 and S13).…”

Synthesis and Applications of (ONO Pincer)Ruthenium‐Complex‐Bound Norvalines

“…Despite the diverse applications of Ru‐bound amino acids, no approach for their catalytic use was reported until Xu and Gilbertson′s reports, in which alanine and its peptides that were conjugated with saturated IMes (SIMes)‐type N‐heterocyclic carbene (NHC)−Ru complex were successfully synthesized and showed catalytic activity for metathesis polymerization . Recently, histidine‐, and tyrosine‐based amino acids that were bound to NHC−Ru complexes were developed and found to be catalytically active for the transfer hydrogenation of ketones and various metathesis reactions, respectively.…”