Organocatalytic Highly Enantioselective Conjugate Addition of Aldehydes to Alkylidine Malonates
作者:Gui-Ling Zhao、Jan Vesely、Junliang Sun、Kirsten E. Christensen、Charlotte Bonneau、Armando Córdova
DOI:10.1002/adsc.200700570
日期:2008.3.25
The first highlyenantioselective, direct organocatalyticconjugateaddition of unmodified aldehydes to alkylidinemalonates is presented. The reaction gives access to β-formyl-substituted malonates and highly functionalized lactones with up to 14:1 dr and generally 94 to >99% ee.
A highlyenantioselective [2+2] cycloaddition reaction of alkylidene malonates with the internal CC bond of N-allenamides was developed with a MgII/N,N′-dioxide complex as a catalyst. Various polysubstituted methylenecyclobutanes were afforded in good yields (up to 99%) and excellent enantioselectivities (up to 96% ee) under mild conditions. The utility of the donor–acceptor cyclobutane product was
以Mg II / N,N'-二氧化物配合物为催化剂,开发了亚烷基丙二酸酯与N-亚酰胺的内部C C键的高对映选择性[2 +2]环加成反应。在温和的条件下,可以提供多种多取代的亚甲基环丁烷,收率好(高达99%)和出色的对映选择性(高达96%ee)。在甲硅烷基烯醇醚的正式[4 + 2]环合反应中,供体-受体环丁烷产品的用途已证明可作为掩蔽的1,4-偶极子。