DNA‐Accelerated Catalysis of Carbene‐Transfer Reactions by a DNA/Cationic Iron Porphyrin Hybrid

Abstract

A novel DNA‐based hybrid catalyst comprised of salmon testes DNA and an iron(III) complex of a cationic meso‐tetrakis(N‐alkylpyridyl)porphyrin was developed. When the N‐methyl substituents were placed at the ortho position with respect to the porphyrin ring, high reactivity in catalytic carbene‐transfer reactions was observed under mild conditions, as demonstrated in the catalytic enantioselective cyclopropanation of styrene derivatives with ethyl diazoacetate (EDA) as the carbene precursor. A remarkable feature of this catalytic system is the large DNA‐induced rate acceleration observed in this reaction and the related dimerization of EDA. It is proposed that high effective molarity of all components of the reaction in or near the DNA is one of the key contributors to this unique reactivity. This study demonstrates that the concept of DNA‐based asymmetric catalysis can be expanded into the realm of organometallic chemistry.

Metal Substitution Modulates the Reactivity and Extends the Reaction Scope of Myoglobin Carbene Transfer Catalysts

“…Co-expression of the chaperone proteins GroEL/ES was found to increase the expression levels of soluble cofactor-substituted Mb, possibly by reducing aggregation of apomyoglobin prior to binding to the non-native cofactor. [14] While these and other studies suggested a certain permissivity of the ChuA transporter toward the uptake of heme analogs containing first-row transition metals, [9c, 14–15] its functionality in the context of metalloporphyrin complexes containing second- and third-row transition metals remained to be determined.…”

“…[7] More recently, biocatalytic systems based on these [8] and other protein and DNA scaffolds have been investigated in the context of carbene transfer reactions. [9] …”

DNA‐Based Asymmetric Inverse Electron‐Demand Hetero‐Diels–Alder

“…In particular, many efforts have been devoted to unveil new biomimetic DNA‐based cycloaddition processes inspired by the seminal [4+2] Diels–Alder cycloaddition– (Figure , A ). This has resulted in the development of various key cycloaddition reactions including a [2+2] photocatalyzed cycloaddition using a benzophenone‐modified DNA as a photosensitizer (Figure , B ) and two cyclopropanation reactions using either a Cu‐dmbipy‐DNA complex or a heme‐DNA artificial enzyme (Figure , C ). Surprisingly, despite all these efforts, there has been no example of an asymmetric DNA‐catalyzed hetero‐Diels–Alder cycloaddition reported in the literature so far.…”

Bioorthogonal Metalloporphyrin‐Catalyzed Selective Methionine Alkylation in the Lanthipeptide Nisin

“…This includes palladium‐ and rhodium‐catalyzed arylations, P450‐catalyzed cyclopropanations and photocatalytic additions . We envisioned the cyclopropanation of dehydroalanine using water‐soluble metalloporphyrins as catalyst and diazo reagents as carbene precursors …”