Seven-membered cyclic transition state in the alkoxy-radical induced intramolecular hydrogen abstraction of 26-hydroxy-furostans

✍ Scribed by Cosme G Francisco; Raimundo Freire; Rosendo Hernández; Maria C Medina; Ernesto Suárez

• Book ID: 104219949
• Publisher: Elsevier Science
• Year: 1983
• Tongue: French
• Weight: 218 KB
• Volume: 24
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(00)85972-9

✦ Synopsis

Surrmary: The photoZysis of 26-hydroxy-furostan ( 5) and (81 in the presence of P~(OAC)&~ afforded spirostan sapogenins ( 4) and ( 7) respectiveZy in 80% yield. This cyclization takes place by an uncommon 1,6-hydrogen shift invoZving a Pmembered transition state as demonstrated by using specifically deuterium labeled compounds.