Ring expansion of a 2-rhodaoxetane: insertion chemistry with unsaturated molecules

Abstract

A 2-rhodaoxetane was found to react with unsaturated electrophiles, such as highly electron-deficient acetylene dicarboxylates, CS2 and various aldehydes, to form a series of six-membered metallacycles. These metallacycles were characterized by (1)H, (13)C and 2D NMR spectroscopic techniques, as well as HRMS and, for one complex, XRD. In some cases, the insertions were found to be reversible.

Synthesis of 2-Nickela(II)oxetanes from Nickel(0) and Epoxides: Structure, Reactivity, and a New Mechanism of Formation

“…Recently, efforts in our group have been focused on the development of new chemical transformations based on the reactivity of well-defined metallaoxetanes of rhodium . We have reported that a 2-rhodaoxetane can undergo transmetalation with aryl- and alkenylboronic acids as well as insertion with a variety of unsaturated electrophiles to give ring-expanded metallacycles .…”

Catalytic Functionalization of Styrenyl Epoxides via 2‐Nickela(II)oxetanes

“…Key to achieving such processes is to develop an understanding of the fundamental reactivity of these complexes. As such, we have demonstrated that 2‐rhodaoxetanes undergo transmetallation with aryl‐and alkenylboronic acids, and ring expansion with various other organic electrophiles . More recently, we have become interested in exploring the feasibility of substituting a cheaper, more earth‐abundant metal, such as nickel, for rhodium.…”

“…Experiments with tetrasubstituted epoxides demonstrate that these reactions proceed via reactive 2-nickelaoxetane intermediates,a nd that the oxidative addition step likely occurs with retention of configuration. [4] More recently,w eh ave becomei nterestedi n exploring the feasibility of substituting ac heaper,m ore earthabundantm etal, such as nickel,f or rhodium. These hydroboration reactions could be performedc atalytically.…”

“…[1] Ongoing research in our group has been focusedo ne xploring the development of new catalytic transformationst hat feature thesem etallaheterocycles as intermediates. [4] More recently,w eh ave becomei nterestedi n exploring the feasibility of substituting ac heaper,m ore earthabundantm etal, such as nickel,f or rhodium. [4] More recently,w eh ave becomei nterestedi n exploring the feasibility of substituting ac heaper,m ore earthabundantm etal, such as nickel,f or rhodium.…”