[CpRu]‐Catalyzed Carbene Insertions into Epoxides: 1,4‐Dioxene Synthesis through S_N1‐Like Chemistry with Retention of Configuration

Abstract

Rather than lead to the usual deoxygenation pathway, metal carbenes derived from α-diazo-β-ketoesters undergo three-atom insertions into epoxides using a combination of 1,10-phenanthroline and [CpRu(CH3CN)3][BAr(F)] as the catalyst. Original 1,4-dioxene motifs are obtained as single regio- and stereoisomers. A perfect syn stereochemistry (retention, e.r. up to 97:3) is observed for the ring opening, which behaves as an S(N)1-like transformation.

[3 + 3]-Cycloaddition of α-Diazocarbonyl Compounds and N-Tosylaziridines: Synthesis of Polysubstituted 2H-1,4-Oxazines through Synergetic Catalysis of AgOTf/Cu(OAc)2

“…In past decades, α-diazocarbonyl compounds have received widespread attention because they can convert into metal–carbene complexes and then react with alkenes, alkynes, or nitriles to deliver cycloaddition products. Doyle and co-workers have made great achievements in this field; they realized a series of cyclization reaction using enoldiazo compounds and proper dipoles.…”

From reactive carbenes to chiral polyether macrocycles in two steps – synthesis and applications made easy?

“…Decomposition of diazo compounds in the presence of oxygen, nitrogen, sulfur or phosphorus Lewis bases is a recognized strategy to generate the corresponding ylides efficiently. 1 In the case of oxonium ylides, diazo reagents decomposed under photochemical or metal-catalyzed conditions 2 are known to react with cyclic ethers such as epoxides, 3 oxetane, 4 THF, 5 THP, 6 1,3-and 1,4-dioxane, 7 or oxepane, 8 and the subsequent intermediates are used in a large panel of reactions including macrocyclization. 7e,9 Macrocyclic molecules are an important class of compounds in nature.…”

One-Step Synthesis of Diaza Macrocycles by Rh(II)-Catalyzed [3 + 6 + 3 + 6] Condensations of Morpholines and α-Diazo-β-ketoesters

“…Decompositions of diazo compounds in the presence of oxygen, nitrogen, sulfur, or phosphorus Lewis bases is a recognized strategy to generate the corresponding ylides efficiently . In the case of oxonium ylides, diazo reagents decomposed by photochemical or metal-catalyzed conditions are known to react with cyclic ethers such as epoxides, oxetanes, THF, THP, 1,3- and 1,4-dioxanes, or oxepane, and the subsequent intermediates are used in a large panel of reactions. However, morpholines, and other N-containing cyclic ethers, are rarely utilized for the formation of oxonium ylides.…”