The stereoselective access to original polyhydroxylated tetrahydropyranopyrroles is described. The key steps involve an inverse-demand Diels-Alder reaction and a ring contraction of a pyridazine heterocycle.
                                    介绍了如何立体选择性地获得原始的多羟基
四氢吡喃。关键步骤包括逆需求 Diels-Alder 反应和
哒嗪杂环的环收缩。