One-Pot, Four-Step Organocatalytic Asymmetric Synthesis of Functionalized Nitrocyclopropanes

The asymmetric synthesis of functionalized
nitrocyclopropanes has
been achieved by a one-pot, four-step method catalyzed by (S)-diphenylprolinol TMS ether, which joins two sequential
domino reactions, namely a domino sulfa-Michael/aldol condensation
of α,β-unsaturated aldehydes with 1,4-dithiane-2,5-diol,
and a domino Michael/α-alkylation reaction of the derived chiral
dihydrothiophenes with bromonitromethane. The title compounds were
obtained in 27–45% yields, with high levels of diastereoselectivity
(93:7 to 100:0 dr) and generally good enantioselectivities (up to
95:5 er).