1433964-28-3Relevant academic research and scientific papers
Mechanism-Driven Elaboration of an Enantioselective Bromocyclopropanation Reaction of Allylic Alcohols
Taillemaud, Sylvain,Diercxsens, Nicolas,Gagnon, Alexandre,Charette, André B.
, p. 14108 - 14112 (2015)
A stereoselective bromocyclopropanation of allylic alcohols using dibromomethylzinc bromide is described. Spectroscopic studies to monitor the formation of transient intermediates not only led to the development of a more-atom-economical halocyclopropanation reaction, but also highlighted the unique role of ether additives in the process. The desired bromo-substituted cyclopropanes were isolated in high yields and excellent diastereo- as well as enantioselectivities using readily available reagents.
Spectroscopic Characterization of Heterohalogenic Dihalomethylzinc Carbenoids: Application to a More Efficient Chlorocyclopropanation Reaction
Charette, André B.,Taillemaud, Sylvain
supporting information, (2022/01/04)
Dihalomethylmetal reagents are important species that can be used in halocyclopropanation reactions (metal = zinc) as well as in alkenyl halide synthesis. When trihalomethanes containing two or more different halogen atoms are used to prepare zinc carbenoids, several species can be formed through a halogen scrambling process. This affects which halocyclopropane, or haloalkene, is generated in the subsequent reaction. In the first part of the paper, we report an extensive characterization of zinc dihalocarbenoids by NMR to identify the major species formed when various di-and trihalomethane reagents are used as carbenoid precursors. In the second part of the paper, a direct application of this information enabled the development of a highly efficient chlorocyclopropanation reaction of allylic alcohols from inexpensive and accessible precursors.
Highly enantioselective synthesis of 1,2,3-substituted cyclopropanes by using α-iodo- and α-chloromethylzinc carbenoids
Beaulieu, Louis-Philippe B.,Zimmer, Lucie E.,Gagnon, Alexandre,Charette, André B.
supporting information, p. 14784 - 14791 (2013/01/15)
Herein, we report the enantio- and diastereoselective formation of trans-iodo- and trans-chlorocyclopropanes from α-iodo- and α-chlorozinc carbenoids by using a dioxaborolane-derived chiral ligand. The synthetically useful iodocyclopropane building blocks were derivatized by an electrophilic trapping of the corresponding cyclopropyl lithium species or a Negishi coupling to give access to a variety of enantioenriched 1,2,3-substituted cyclopropanes. The synthetic utility of this method was demonstrated by the formal synthesis of an HIV-1 protease inhibitor. In addition, the related stereoselective bromocyclopropanation was also investigated. New insights about the relative electrophilicity of haloiodomethylzinc carbenoids are also presented. Propping up the enantioselectivity: The enantio- and diastereoselective formation of trans-iodo- and trans-chlorocyclopropanes from α-iodo- and α-chlorozinc carbenoids by using a dioxaborolane-derived chiral ligand is reported. The iodocyclopropanes were derivatized into a variety of 1,2,3-substituted cyclopropanes and new insights into the relative electrophilicity of α-haloiodomethylzinc carbenoids are presented (see scheme). Copyright
