A synthesis of (−)-tashiromine and formal synthesis of (+)-tashiromine utilizing a highly enantioselective pyrrole/cobaloxime π-cation cyclization
摘要:
Cyclization of (5-N-pyrrolyl-2-hydroxypentyl)cobaloxime (13) proceeds by intramolecular electrophilic aromatic substitution of a cobaloxime pi-cation onto the pyrrole ring to provide 6-exo cyclization product (14) in 95% yield. This cyclization is highly enantioselective. It is applied to a synthesis of highly enantioenriched (-)-tashiromine, (-)-21, and a formal synthesis of (+)-tashiromine. (C) 1997 Elsevier Science Ltd.
DOI:
10.1016/s0040-4039(97)01638-9
作为产物:
描述:
alkaline earth salt of/the/ methylsulfuric acid 生成 1,5-二乙酰基氧基-2-乙酸戊酯
参考文献:
名称:
Paul, Comptes Rendus Hebdomadaires des Seances de l'Academie des Sciences, 1939, vol. 208, p. 588
Cyclic ethers such as tetrahydrofuran or tetrahydropyran were easily cleaved at room temperature by sulfuricacid - aceticanhydride providing the corresponding diacetoxyalkanes in good yield. The ring opening was applicable to saturated cyclic ethers, regardless of the presence of substituent groups.