1451929-27-3Relevant academic research and scientific papers
Iridium-Catalyzed Enantioselective C(sp3)–H Borylation of Cyclobutanes
Chen, Xiang,Chen, Lili,Zhao, Hongliang,Gao, Qian,Shen, Zhenlu,Xu, Senmiao
supporting information, p. 1533 - 1537 (2020/09/09)
We herein report the first example of iridium-catalyzed enantioselective C(sp3)–H borylation of cyclobutanes using benzoxazoline as the directing group. The combination of a chiral bidentate boryl ligand and an iridium precursor has found to effectively catalyze C(sp3)–H borylation to afford a variety of cyclobutylboronates with good to excellent enantioselectivities. We also demonstrate the synthetic utility of the current method by converting the stereogenic C—B bond to other functionalities.
Improvements and Applications of the Transition Metal-Free Asymmetric Allylic Alkylation using Grignard Reagents and Magnesium Alanates
Grassi, David,Alexakis, Alexandre
supporting information, p. 3171 - 3186 (2015/11/03)
Two new N-heterocyclic carbene (NHC) ligands have been synthesized and employed in the transition metal-free asymmetric allylic alkylation (AAA) mediated by Grignard reagents and magnesium alanates. The employment of these ligands showed high yields and improved regio- and enantioselectivity in the formation of tertiary and quaternary stereocenters. Moreover, the low catalyst loading (up to 0.3 mol%) and high scalability (up to 10 mmol) of this improved methodology provide a convenient access to biologically active compounds and synthetically valuable intermediates.
Copper-free asymmetric allylic alkylation with a grignard reagent: Design of the ligand and mechanistic studies
Grassi, David,Dolka, Chrysanthi,Jackowski, Olivier,Alexakis, Alexandre
supporting information, p. 1466 - 1475 (2013/02/25)
The Cu-free asymmetric allylic alkylation, catalysed by NHC, with Grignard reagents is reported on allyl bromide derivatives with good results. The enantioselectivity was quite homogeneous (around 85 % ee) on large and various substrates, regardless of the nature of the Grignard reagent. The formation of stereogenic quaternary centres was highly regioselective for both aliphatic and aromatic derivatives with good enantiomeric excess (up to 92 % ee). The methodology developed was found to be complementary with the Cu-catalysed version. Several new NHCs were tested with improved efficiency. In addition, mechanistic studies, using NMR spectroscopy, led to the discovery of the catalytically active species. Copyright
