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A system of three coupled catalytic cycles enabling the one-pot transformation of epoxides to amines via Meinwald rearrangement, imine condensation, and imine reduction is described. This assisted tandem catalysis is catalyzed by B(C6F5)3 resulting in the first tandem Meinwald rearrangement-reductive amination protocol. The reaction proceeds in nondried solvents and yields β-functionalized amines. In particular, β-diarylamines are obtained in high yields.

Iron complexes derived from a bis-isoindoline-bis-pyridine ligand platform based on the BPBP ligand (BPBP = N,N′-bis(2-picolyl)-2,2′-bis-pyrrolidine) have been synthesized and applied in selective aliphatic C–H oxidation with hydrogen peroxide under mild conditions. The introduction of benzene moieties on the bis-pyrrolidine backbone leads to an increased preference of tertiary over secondary C–H bond oxidation (3°/2° ratio up to 33). On the other hand, substituting the meta-position of the pyridines with bulky silyl groups affords enhanced secondary C–H oxidation selectivity and generally leads to higher product yields and mass balances.

The selective synthesis of purely organic cages withhetero-sequenced functionalized cavities is demonstrated. Thestrategy to obtain these compounds is based on a stepwiseapproach using thermodynamically controlled imine condensa-tions. To accomplish this, the amine building blocks carry addi-tional azide groups, which act as masked amines and enablethe synthesis of the desired cavities. This approach offers a precise control of interior functionalization, the substitution pat-tern and the cage size, which is demonstrated by the selectivesynthesis of four cages. The largest described cage has beeninvestigated towards its ability for guest encapsulation and isable to selectively encapsulate functionalized arenes that offera matching substitution pattern.

The selective synthesis of purely organic cages withhetero-sequenced functionalized cavities is demonstrated. Thestrategy to obtain these compounds is based on a stepwiseapproach using thermodynamically controlled imine condensa-tions. To accomplish this, the amine building blocks carry addi-tional azide groups, which act as masked amines and enablethe synthesis of the desired cavities. This approach offers a precise control of interior functionalization, the substitution pat-tern and the cage size, which is demonstrated by the selectivesynthesis of four cages. The largest described cage has beeninvestigated towards its ability for guest encapsulation and isable to selectively encapsulate functionalized arenes that offera matching substitution pattern.

A system of three coupled catalytic cycles enabling the one-pot transformation of epoxides to amines via Meinwald rearrangement, imine condensation, and imine reduction is described. This assisted tandem catalysis is catalyzed by B(C6F5)3 resulting in the first tandem Meinwald rearrangement-reductive amination protocol. The reaction proceeds in nondried solvents and yields β-functionalized amines. In particular, β-diarylamines are obtained in high yields.

Mononuclear iron(II) complexes with facially coordinating N,N,O-ligands were synthesized as accurate structural mimics of the 2-His-1-carboxylate facial triad found in mononuclear non-heme iron enzymes. Mimicking of the facial triad is achieved by designing sterically demanding ligands providing two histidine-like benzimidazole moieties and a coordinating carboxylate or ester moiety. The new methyl-substituted analogue of the bis(benzimidazolyl)propionate ligand, BMBMeIP and its ester analogue, BMBMeIPnPr are designed to prevent the formation of previously reported coordinatively saturated FeL2 type complexes. The crystal structure of [Fe(BMBMeIPnPr)(OTf)2] shows a facial N,N,O-coordination that is very similar to the structure of the enzyme active sites. Both [Fe(BMBMeIPnPr)(OTf)2] and [Fe(BMBMeIP)(OTf)(MeCN)n] catalyze the epoxidation of olefins using H2O2, reaching turnover numbers up to 5.8 per iron. These results represent the first examples of iron complexes bearing a single facial and rigid N,N,O-coordinating ligand and three readily available coordination sites showing catalytic activity in oxidation reactions.

The first shape-persistent macrocycle 1 offering a Brønsted pair functionalized interior is described. Via postcyclization transformation, this heterosequenced compound can be obtained from its corresponding ester 2. The macrocycles differ dramatically in their characteristics such as solubility and appearance. Theoretical investigations suggest that those contrasts might originate from conformational changes due to the formation of a strong O-H-N hydrogen bond in 1.

A method for the regioselective transformation of dienes to carbonyl compounds has been developed. Electron-rich olefins react selectively to yield valuable aldehydes and ketones. The method is based on the catalyst [Fe(OTf)2(mix-BPBP)] with an oxidant combination of H2O2 (1.0 equiv.) and NaIO4 (1.5 equiv.); it uses mild conditions and short reaction times, and it outperforms other olefin cleavage methodologies. The combination of an Fe-based catalyst, [Fe(OTf)2(mix-BPBP)], and the oxidants H2O2 and NaIO4 can discriminate between electronically different double bonds and oxidatively cleave the electron-rich bond in dienes to yield aldehydes and ketones in a regioselective manner. The reaction requires mild conditions (0-50 C) and short reaction times (70 min).

Mononuclear iron(II) complexes with facially coordinating N,N,O-ligands were synthesized as accurate structural mimics of the 2-His-1-carboxylate facial triad found in mononuclear non-heme iron enzymes. Mimicking of the facial triad is achieved by designing sterically demanding ligands providing two histidine-like benzimidazole moieties and a coordinating carboxylate or ester moiety. The new methyl-substituted analogue of the bis(benzimidazolyl)propionate ligand, BMBMeIP and its ester analogue, BMBMeIPnPr are designed to prevent the formation of previously reported coordinatively saturated FeL2 type complexes. The crystal structure of [Fe(BMBMeIPnPr)(OTf)2] shows a facial N,N,O-coordination that is very similar to the structure of the enzyme active sites. Both [Fe(BMBMeIPnPr)(OTf)2] and [Fe(BMBMeIP)(OTf)(MeCN)n] catalyze the epoxidation of olefins using H2O2, reaching turnover numbers up to 5.8 per iron. These results represent the first examples of iron complexes bearing a single facial and rigid N,N,O-coordinating ligand and three readily available coordination sites showing catalytic activity in oxidation reactions.

The first shape-persistent macrocycle 1 offering a Brønsted pair functionalized interior is described. Via postcyclization transformation, this heterosequenced compound can be obtained from its corresponding ester 2. The macrocycles differ dramatically in their characteristics such as solubility and appearance. Theoretical investigations suggest that those contrasts might originate from conformational changes due to the formation of a strong O-H-N hydrogen bond in 1.