| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1350879 | Tetrahedron: Asymmetry | 2005 | 9 Pages |
A series of new chiral oxazoline-1,3-dithianes has been easily synthesized and used as ligands for asymmetric catalysis. The conjugate addition of Et2Zn to enones resulted in ees of up to 69%, whereas the Pd-catalyzed allylic alkylation led to the expected products in almost quantitative yields and up to 90% enantioselectivity. The ligand’s conformation has been explored using a combination of X-ray and NMR measurements, indicating the presence of a remarkable anomeric effect, which accounts for the preference of the oxazoline ring for the axial location.
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(4S)-4-Benzyl-2-(l,3-dithian-2-yl)-4,5-dihydro-1,3-oxazoleC14H17NOS2Ee >99%[α]D20=-19 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)
(4S)-4-Benzyl-2-(2-methyl-1,3-dithian-2-yl)-4,5-dihydro-1,3-oxazoleC15H19NOS2Ee >99%[α]D20=-28 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)
(4S)-4-Isopropyl-2-(2-methyl-1,3-dithian-2-yl)-4,5-dihydro-1,3-oxazoleC11H19NOS2Ee >99%[α]D20=-64 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)
(4S)-4-tert-Butyl-2-(2-methyl-1,3-dithian-2-yl)-4,5-dihydro-1,3-oxazoleC11H21NOS2Ee >99%[α]D20=-68 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (S)
(4S,5S)-4-Methyl-2-(2-methyl-1,3-dithian-2-yl)-5-phenyl-4,5-dihydro-1,3-oxazoleC15H19NOS2Ee >99%[α]D20=+40 (c 0.3, CHC13)Source of chirality: asymmetric synthesisAbsolute configuration: (S,S)
(4R,5R)-4-Methyl-2-(2-methyl-1,3-dithian-2-yl)-4,5-diphenyl-4,5-dihydro-1,3-oxazoleC20H21NOS2Ee >99%[α]D20=+77 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,R)
(3aR,8aS)-2-(2-Methyl-1,3-dithian-2-yl)-8,8a-dihydro-3aH-indeno-[l,2-d]-[l,3]-oxazoleC15H17NOS2Ee >99%[α]D20=+175 (c 0.3, CHCl3)Source of chirality: asymmetric synthesisAbsolute configuration: (R,S)
