cyclization reaction of dioxopyrrolidines and azlactones has been successfully developed through a squaramide catalysis strategy. This protocol provides an efficient and mild access to obtain pyrano[2,3-c]pyrrole scaffolds containing contiguous quaternary and tertiary stereogenic centers in excellent yields (up to 99%) with high levels of diastereo- and enantioselectivities (up to 99% ee). Two possible pathways
二氧
吡咯烷和氮杂内酯的对映选择性[4 + 2]环化反应已通过方酰胺催化策略成功开发。该协议提供了高效,温和的途径来获得
吡喃并[2,3- c ]
吡咯支架,该支架包含连续的四级和三级立体异构中心,产率高(高达99%),非对映和对映选择性高(ee高达99%) )。提出了两种可能的途径来解释观察到的立体选择性。