Manganese catalysed asymmetric cis-dihydroxylation with H2O2

Abstract

High turnover enantioselective alkene cis-dihydroxylation is achieved with H(2)O(2) catalysed by manganese based complexes containing chiral carboxylato ligands.

Redox‐State Dependent Ligand Exchange in Manganese‐Based Oxidation Catalysis

“…The later observation that moderate (up to 54 %) enantioselectivity in cis-dihydroxylation could be achieved by using chiral carboxylic acids confirmed that the form of the catalyst engaged in oxygen transfer bears at least one carboxylato ligand. [174] Although, mononuclear high-valent species are frequently proposed as the active species in regard to oxygen transfer to substrate, the data available support the involvement of dinuclear structures that are similar to 9a. 18 O labelling studies.…”

Manganese‐Catalyzed Oxidation with Hydrogen Peroxide

“…Recent success in using iron-based systems by Que and coworkers [127] demonstrated that the challenge may yet be met. Recently, Feringa and coworkers demonstrated [128] that the Mn-tmtacn based catalytic system employing carboxylic acids can be used for asymmetric cis-dihydroxylation of an electron-rich cis-alkene -ironically a notably challenging substrate in the case of the osmium-based systems. Importantly, the manganese-based catalytic system for AD of alkenes developed employs H 2 O 2 as the oxidant.…”

“…In sharp contrast, Scheme 11.16 Asymmetric cis-dihydroxylation (AD) of 2,2-dimethylchromene with H 2 O 2 catalyzed by the system 6/R-CO 2 H (¼acetyl-D-phenylglycine) [128]. Scheme 11.17 Epoxidation with Mn-tptn catalyst and structures of manganese complexes [132].…”

Highly Enantioselective Iron‐Catalyzed cis‐Dihydroxylation of Alkenes with Hydrogen Peroxide Oxidant via an FeIII‐OOH Reactive Intermediate

“…

The development of environmentally benign catalysts for highly enantioselective asymmetric cis-dihydroxylation (AD) of alkenes with broad substrate scope remains ac hallenge.B ye mploying [Fe II (L)(OTf) 2 ]( L = N,N'dimethyl-N,N'-bis(2-methyl-8-quinolyl)-cyclohexane-1,2-diamine) as ac atalyst, cis-diols in up to 99.8 %e ew ith 85 % isolated yield have been achieved in AD of alkenes with H 2 O 2 as an oxidant and alkenes in al imiting amount. [10,11] An enantioselectivity of > 90 % ee was reported for a-[Fe II (R,R-6-Me 2 -BPBP)(OTf) 2 ]-catalyzed AD of electron-rich alkenes (E)-2-octene and (E)-2-heptene (96-97 % ee); the method, which was developed by Que and co-workers,employed H 2 O 2 as at erminal oxidant and alkenes in a5 0-fold excess. Mechanistic studies,i ncluding 18 O-labeling,U V/Vis, EPR, ESI-MS analyses,a nd DFT calculations lend evidence for the involvement of chiral Fe III -OOH active species in enantioselective formation of the two CÀOb onds.

Asymmetric cis-dihydroxylation (AD) of alkenes,u sually using osmium reagents,i sa ni mportant reaction in organic synthesis.

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“…[3b] On the other hand, notable progress has been achieved for alkene cis-dihydroxylation with non-osmium metal compounds, [1d, 4] including that of ruthenium, [4b, 5] manganese, [4d, 6, 7] and iron. [10,11] An enantioselectivity of > 90 % ee was reported for a-[Fe II (R,R-6-Me 2 -BPBP)(OTf) 2 ]-catalyzed AD of electron-rich alkenes (E)-2-octene and (E)-2-heptene (96-97 % ee); the method, which was developed by Que and co-workers,employed H 2 O 2 as at erminal oxidant and alkenes in a5 0-fold excess. [10,11] An enantioselectivity of > 90 % ee was reported for a-[Fe II (R,R-6-Me 2 -BPBP)(OTf) 2 ]-catalyzed AD of electron-rich alkenes (E)-2-octene and (E)-2-heptene (96-97 % ee); the method, which was developed by Que and co-workers,employed H 2 O 2 as at erminal oxidant and alkenes in a5 0-fold excess.…”