The Isopropylsulfinyl Group: A Useful Chiral Controller for the Asymmetric Aziridination of Sulfinylimines and the Organocatalytic Allylation of Hydrazones
摘要:
A comparative study shows that the isopropylsulfinyl group for which an enantiodivergent and highly diastereoselective approach is reported behaves better than the tert-butylsulfinyl and p-tolylsulfinyl groups, both in terms of reactivity and stereoselectivity in the Corey-Chaykovsky reaction of chiral sulfinylimines and the organocatalytic allylation of acyl hydrazones.
<i>N</i>-Isopropylsulfinylimines<i>vs. N-tert</i>-butylsulfinylimines in the stereoselective synthesis of sterically hindered amines: an improved synthesis of enantiopure (<i>R</i>)- and (<i>S</i>)-rimantadine and the trifluoromethylated analogues
An improved fully stereoselective synthesis of both enantiomers of rimantadine and its trifluoromethylated analogues has been developed, using N-isopropylsulfinylimines as a starting chiral material, proving the superiority of the isopropyl group as a chiral inducer over the tert-butyl group in the case of hindered N-sulfinylimines.
DMAP-Catalysed Sulfinylation of Diacetone-<scp>D</scp>-Glucose: Improved Method for the Synthesis of Enantiopure<i>tert</i>-Butyl Sulfoxides and<i>tert</i>-Butanesulfinamides
enantioselectivities. (RS)-DAG sulfinate ester 2RS is also an excellent N-sulfinylating agent; simple addition of LiHMDS (lithium hexamethyldisilazide) in THF gives (SS)-tert-butanesulfinamide, and N-tert-butanesulfinylimines are then formed in a two-step one-pot manner. N-Alkylated tert-butanesulfinamides are formed by the condensation of 2RS with lithiumamides.
Reported herein is a straightforward and enantiodivergent synthesis of both enantiomers of trifluoromethylatedanalogues of calcimimeticNPS R-569 in a highly estereoselective manner. The synthesis features a diastereoselective synthesis of the N-(isopropylsulfinyl)imine unit by the "DAG methodology" and a diastereoselective addition of Ruppert-Prakash's reagent to the imine as the key steps. No protecting