3-substituted thiopyran-4-ones is reported for the first time via aldol condensation of various aromatic aldehydes with dihydrothiopyran-4-one derivatives under very mild conditions using magnesiumbromide diethyl etherate and triethyl-amine. The products were characterized based on spectroscopic and X-ray diffraction experiments.
Switching the Reactivity of Dihydrothiopyran-4-one with Aldehydes by Aqueous Organocatalysis: Baylis–Hillman, Aldol, or Aldol Condensation Reactions
作者:M. Saeed Abaee、Mohammad M. Mojtahedi、Ghasem F. Pasha、Elahe Akbarzadeh、Abbas Shockravi、A. Wahid Mesbah、Werner Massa
DOI:10.1021/ol202145w
日期:2011.10.7
An aqueous medium containing catalytic amounts of a tertiary amine was employed to direct the chemoselectivity of the reaction of aldehydes with 1a. With DBU, 2 was formed at room temperature as a rare exemplary of Baylis–Hillman reactions in heterocyclic enones. DABCO alternated the pathway toward an aldol reaction to form syn/anti mixtures of 3 with the syn isomers being the major products. With