1435903-30-2Relevant academic research and scientific papers
A synthetic and spectroscopic investigation of the asymmetric α-lithiation-trapping of six-membered N-Boc heterocycles using Alexakis diamines
Firth, James D.,Gelardi, Giacomo,Rayner, Peter J.,Stead, Darren,O’Brien, Peter
, p. 1288 - 1303 (2019/07/31)
– The asymmetric lithiation-trapping of six-membered N-Boc heterocycles using s-BuLi and two different Alexakis diamines is reported. These readily available ligands outperform the current ‘best-in-class’ sparteine-type diamines in the lithiation and benz
Preparation and reactions of enantiomerically pure α-functionalized grignard reagents
Rayner, Peter J.,O'Brien, Peter,Horan, Richard A. J.
supporting information, p. 8071 - 8077 (2013/07/11)
A strategy for the generation of enantiomerically pure α- functionalized chiral Grignard reagents is presented. The approach involves the synthesis of α-alkoxy and α-amino sulfoxides in ≥99:1 dr and ≥99:1 er via asymmetric deprotonation (s-BuLi/chiral diamine) and trapping with Andersen's sulfinate (menthol derived). Subsequent sulfoxide → Mg exchange (room temperature, 1 min) and electrophilic trapping delivers a range of enantiomerically pure α-alkoxy and α-amino substituted products. Using this approach, either enantiomer of products can be accessed in 99:1 er from asymmetric deprotonation protocols without the use of (-)-sparteine as the chiral ligand. Two additional discoveries are noteworthy: (i) for the deprotonation and trapping with Andersen's sulfinate, there is a lack of stereospecificity at sulfur due to attack of a lithiated intermediate onto the α-alkoxy and α-amino sulfoxides as they form, and (ii) the α-alkoxy-substituted Grignard reagent is configurationally stable at room temperature for 30 min.
