Reinvestigation of the Biomimetic Cyclization of 3,5-Diketo Esters: Application to the Total Synthesis of Cyercene A, an α-Methoxy-γ-Pyrone-Containing Polypropionate
作者:Akira Sakakura、Kai Onda、Ichiro Hayakawa
DOI:10.1055/s-0036-1588795
日期:2017.8
The biomimetic cyclization of 3,5-diketo esters was reinvestigated for the synthesis of α-methoxy-γ-pyrones. 3,5-Diketo esters were selectively synthesized via the aldol reaction of commercially available methyl 2-methyl-3-oxopentanoate with an aldehyde followed by the oxidation with AZADOL ® and PhI(OAc) 2 . The DBU-promoted intramolecular transesterification of 3,5-diketo esters showed excellent
重新研究了 3,5-二酮酯的仿生环化以合成 α-甲氧基-γ-吡喃酮。通过市售的 2-甲基-3-氧代戊酸甲酯与醛的羟醛反应,然后用 AZADOL ® 和 PhI(OAc) 2 氧化,选择性合成 3,5-二酮酯。DBU 促进的 3,5-二酮酯的分子内酯交换在 MeOH 中显示出优异的反应性,在温和的反应条件下以高产率得到相应的 γ-羟基-α-吡喃酮。基于该环化方案,实现了萜烯A的全合成。