Ward Dale E, Jheengut Vishal, Akinnusi Olukayode T
Department of Chemistry, University of Saskatchewan, Saskatoon SK S7N 5C9, Canada.
Org Lett. 2005 Mar 17;7(6):1181-4. doi: 10.1021/ol050195l.
[reaction: see text] Proline-catalyzed aldol reactions of tetrahydro-4H-thipyranone with racemic 1,4-dioxa-8-thia-spiro[4.5]decane-6-carboxaldehyde and with meso/dl 1,4-dioxa-8-thiaspiro[4.5]decane-6,10-dicarboxaldehyde proceed with dynamic kinetic resolution and give single adducts in good yields with excellent ee's. The high enantiotopic group selectivity results from the high intrinsic diastereoface selectivity of the aldehydes. These reactions significantly extend the scope of the enantioselective direct aldol reaction and constitute simple and efficient syntheses of useful tetrapropionate synthons.
[反应：见正文] 脯氨酸催化四氢-4H-噻喃酮与外消旋1,4-二氧杂-8-硫杂螺[4.5]癸烷-6-甲醛以及内消旋/外消旋1,4-二氧杂-8-硫杂螺[4.5]癸烷-6,10-二甲醛的羟醛反应通过动态动力学拆分进行，以良好的产率和优异的对映体过量值得到单一加合物。高对映异位基团选择性源于醛的高固有非对映面选择性。这些反应显著扩展了对映选择性直接羟醛反应的范围，并构成了有用的四丙酸合成子的简单高效合成方法。
