Artificial Metalloenzymes for Hydrogenation and Transfer Hydrogenation ReactionsReview
Artificial Metalloenzymes and MetalloDNAzymes in Catalysis: From Design to Applications 2018, 171-197, 10.1002/9783527804085.ch6
The development of artificial hydrogenases (AHases) and transfer hydrogenases (ATHases) has played a leading and guiding role for the field of artificial metalloenzymes. Starting from the early studies by Whitesides and coworkers, this chapter showcases the conceptual development of AHases and ATHases, highlighting the different conjugation strategies used for their construction and exemplifying the stereoselective control in product formation that can be reached.
Notes: Book chapter
Covalent Anchoring of a Racemization Catalyst to CALB-Beads: Towards Dual Immobilization of DKR Catalysts
Tetrahedron Lett. 2011, 52, 1601-1604, 10.1016/j.tetlet.2011.01.106
The preparation of a heterogeneous bifunctional catalytic system, combining the catalytic properties of an organometallic catalyst (racemization) with those of an enzyme (enantioselective acylation) is described. A novel ruthenium phosphonate inhibitor was synthesized and covalently anchored to a lipase immobilized on a solid support (CALB, Novozym® 435). The immobilized bifunctional catalytic system showed activity in both racemization of (S)-1-phenylethanol and selective acylation of 1-phenylethanol.
Ligand type: CO; Tetraphenyl cyclopentadieneHost protein: Lipase B from C. antarctica (CALB)Reaction: AcylationMax TON: ---ee: >99%PDB: ---Notes: Lipase CALB is immobilized on a solid support (Novozym®435). Dynamic kinetic resolution (DKR) of 1-phenylethanol to the acylated product.
Lipase Active Site Covalent Anchoring of Rh(NHC) Catalysts: Towards Chemoselective Artificial Metalloenzymes
Chem. Commun. 2015, 51, 6792-6795, 10.1039/c4cc09700a
A Rh(NHC) phosphonate complex reacts with the lipases cutinase and Candida antarctica lipase B resulting in the first (soluble) artificial metalloenzymes formed by covalent active site-directed hybridization. When compared to unsupported complexes, these new robust hybrids show enhanced chemoselectivity in the (competitive) hydrogenation of olefins over ketones.
Metal: RhOptimization: ---Reaction: HydrogenationMax TON: 20ee: rac.PDB: 1CEXNotes: ---
Metal: RhHost protein: Lipase B from C. antarctica (CALB)Optimization: ---Reaction: HydrogenationMax TON: 20ee: rac.PDB: 4K6GNotes: ---
Ring-Closing and Cross-Metathesis with Artificial Metalloenzymes Created by Covalent Active Site- Directed Hybridization of a Lipase
Chem. - Eur. J. 2015, 21, 15676-15685, 10.1002/chem.201502381
A series of Grubbs‐type catalysts that contain lipase‐inhibiting phosphoester functionalities have been synthesized and reacted with the lipase cutinase, which leads to artificial metalloenzymes for olefin metathesis. The resulting hybrids comprise the organometallic fragment that is covalently bound to the active amino acid residue of the enzyme host in an orthogonal orientation. Differences in reactivity as well as accessibility of the active site by the functionalized inhibitor became evident through variation of the anchoring motif and substituents on the N‐heterocyclic carbene ligand. Such observations led to the design of a hybrid that is active in the ring‐closing metathesis and the cross‐metathesis of N,N‐diallyl‐p‐toluenesulfonamide and allylbenzene, respectively, the latter being the first example of its kind in the field of artificial metalloenzymes.
Reaction: Olefin metathesisMax TON: 17ee: ---PDB: ---Notes: RCM