Synthesis of allenic diols by samarium diiodide-promoted coupling between alkynyloxiranes and ketones
作者:JoséM. Aurrecoechea、Eva Alonso、Mónica Solay
DOI:10.1016/s0040-4020(98)00110-0
日期:1998.4
The SmI2-mediated reductive coupling between alkynyloxiranes and ketones provides a new route to 2,3-pentadiene-1,5-diols. The preferred stereochemistry observed in the coupling products is the result of the new CC bond forming anti with respect to the opening epoxide ring. Yields and diastereoselectivities are dependent on the alkynyloxirane substitution pattern.
On the chemoselectivity of formation of 2-(α-hydroxyalkyl)-2,5-dihydrofurans from allenic diols
作者:JoséM. Aurrecoechea、Mónica Solay
DOI:10.1016/s0040-4020(98)00111-2
日期:1998.4
The Ag(I)-promoted cyclization of 2,5-pentadiene-1,5-diols containing both a tertiary and a secondary or primary hydroxyl group, has been examined. In general, the reaction displays a preference for cyclization through the more hindered tertiary hydroxyl group, sometimes to the exclusion of alternative pathways involving secondary or primary carbinol centers.