Organocatalyst-mediated enantioselective intramolecular Michael addition of aldehydes to vinyl sulfones

Chiral amines with a hydrogen bond donor promote the intramolecular conjugate addition of aldehydes to vinyl sulfones. Chiral cyclic sulfone-aldehydes are obtained in good yields with an ee of up to 82%.

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2-Phenylsulfonylmethyl-cyclopentanecarbaldehydeC13H16O3See = 65 %[α]D20=-5.5 (c 0.3, CHCl3)Source of chirality: asymmetric synthesis

2-(Pyridine-2-sulfonylmethyl)-cyclopentanecarbaldehydeC12H15NO3See = 67%[α]D25=-10.3 (c 0.57, CHCl3)Source of chirality: asymmetric synthesis

2-(4-Nitro-phenylsulfonylmethyl)-cyclopentanecarbaldehydeC13H15NO5See = 72%[α]D25=-0.7 (c 0.74, CHCl3)Source of chirality: asymmetric synthesis

2-(3,5-Bis-trifluoromethyl-phenylsulfonylmethyl)-cyclopentanecarbaldehydeC15H14F6O3See = 82 %[α]D20=+0.5 (c 1.54, CHCl3)Source of chirality: asymmetric synthesis