Iron(III) Corroles and Porphyrins as Superior Catalysts for the Reactions of Diazoacetates with Nitrogen‐ or Sulfur‐Containing Nucleophilic Substrates: Synthetic Uses and Mechanistic Insights

Abstract

A thorough mechanistic investigation has been performed on the reactions of primary and secondary amines with diazoacetates, which proceed uniquely quickly and efficiently when catalyzed by iron(III) corroles and porphyrins. Two major differences in relation to other metal-based catalysts are that the iron complexes are not poisoned by excess amine and that metal-carbene intermediates are apparently not involved in the reaction pathway. The results instead point towards nitrogen ylide intermediates formed by nucleophilic attack of the amines on diazoacetate-coordinated iron complexes. Nitrogen ylides are also formed when allyl- and propargyl-substituted tertiary amines react with diazoacetates, a scenario that smoothly leads to 2,3-rearrangement reaction products with catalytic amounts of the iron(III) complexes. Similar findings regarding the superiority of the iron(III) complexes (in terms of catalyst loading, chemical yields, and reaction conditions) were obtained with thiols (S--H insertion) and sulfides (2,3-rearrangement reactions), which suggest similar mechanisms operate in these cases.

Diazo ester insertion in NH bonds of amino acid derivatives and insulin catalyzed by water-soluble iron and ruthenium porphyrin complexes (FeTSPPCl) as application of carbenoid transfer in aqueous media

“…Iron porphyrin-catalyzed NH insertions have been previously studied in organic solvents [15][16][17][18]. Aviv and Gross [18] also reported intermolecular N H insertion of anilines in water/THF catalyzed by myoglobin.…”

Bulk Gold-Catalyzed Reactions of Diazoalkanes with Amines and O2 to Give Enamines

“…But this reaction also gave a 66% yield of 15 even in the absence of the gold catalyst under the same conditions. Although this reaction has been reported to be catalyzed by complexes of Ru, Fe, and Cu [33][34][35][36][37][38][39][40][41][42][43][44][45], we are not aware of a previous report of the uncatalyzed reaction. …”

“…4) when catalyzed by a variety of homogeneous transition metal complexes. For reviews involving catalyzed diazo compound N-H insertion reactions, see: [33][34][35][36][37][38][39][40][41][42][43][44]. For examples of highly enantioselective metal-catalyzed intermolecular carbenoid N-H insertion reactions, see: [45].…”

Synthesis and chemical reactivity of new zinc porphyrin diazoacetates catalyzed by ruthenium and iron porphyrins

“…22 The insertion of electrophilic carbenes in the N-H bonds of protected -amino esters or amides is a powerful method for N-alkylating this class of compounds. 23 Since we 7,8 and others [24][25][26][27] previously reported N-H insertion of diazoesters catalyzed by metalloporphyrins (Fe, Ru), N-H insertion with a diazo porphyrin ester was also investigated (Scheme 2). The results presented in Scheme 2 show that the iron complex is a good catalyst for the transformation of tryptophan methyl ester into the expected N-H inserted products with 69%…”

“…Treatment of thiophenol with diazoporphyrin ester catalyzed by complex 1a gave insertion of the diazo derivative into the S-H bond with 85 % yield. The mechanisms of the cyclopropanation reaction, N-H insertion and S-H insertion, catalyzed by metalloporphyrins, have been previously discussed by us 8 and others [25][26][27] several times, and will not be presented herein. All the new derivatives were identified by NMR and mass spectral analysis.…”