2848-06-8Relevant academic research and scientific papers
Enantioselective Synthesis of cis- A nd trans-Borocyclopropylmethanol: Simple Building Blocks to Access Heterocycle-Substituted Cyclopropylmethanols
Charette, André B.,Navuluri, Chandrasekhar,Siddiqui, Saher H.
, p. 3834 - 3846 (2019/10/11)
An enantioselective and non-oxidative methodology was developed to obtain enantioenriched cyclopropyl boronates using a diethanolamine-promoted selective decomplexation of dioxaborolane. The non-oxidative decomplexation of the dioxaborolane ligand from the cyclopropylmethoxide species formed in the dioxaborolane-mediated Simmons-Smith cyclopropanation reaction provided the enantio?-enriched CIDA-based (CIDA = N-cyclohexyliminodiacetic acid) boro?-cyclopropane in 92% yield and 95.6:4.4 er. A robustness screen has shown diethanolamine to be compatible with esters, carbamates and N-heterocycles, providing a tool to access enantioenriched cyclopropanes carrying not only base-sensitive but oxidizable functional groups as well. Diethanolamine was found to be compatible with the modified zinco-cyclopropanation reaction of allyl alcohol to remove residual dioxaborolane from the corresponding cis-N-heterocycle cyclopropylmethanol, thereby leading to improved yields.
