Acid-Catalyzed Rearrangements of 5,6-exo-Epoxy-7-oxabicyclo[2.2.1]hept-2-yl Derivatives. Migratory Aptitudes of Acylvs. Alkyl Groups inWagner-Meerwein Transpositions
作者:Claude Le Drian、Pierre Vogel
DOI:10.1002/hlca.19870700706
日期:1987.11.4
(6a, b) gave products derived from the epoxide-ring opening and a 1,2-shift of the unsubstituted alkyl group (σ bond C(3)–C(4)). In contrast, under similar conditions, the 5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one (6c) gave 5-oxo-2-oxabicyclo[2.2.1]heptane-3,7-diyl diacetates 20 and 21 arising from the 1,2-shift of the acyl group. Acid treatment of 5,6-exo-epoxy-2,2-dimethoxy-7-oxabicyclo[2.2.1]heptane
在HSO的存在3 F / AC 2 ö在CH 2 CL 2,2-外-和2-内型-氰基-5,6-外-环氧-7-氧杂双环〔2.2.1〕庚-2-基乙酸酯(6a,b)给出了从环氧化物的开环和未取代的烷基(σ键C(3)–C(4))的1,2-移位衍生的产物。相比之下,在相似的条件下,5,6- exo -epoxy-7-oxabicyclo [2.2.1]庚-2--2-(6c)得到5-oxo-2-oxabicyclo [2.2.1]庚烷-3,7 -由酰基的1,2-移位产生的-二乙酸二乙酯20和21。5,6- exo的酸处理-环氧-2,2-二甲氧基-7-氧杂双环[2.2.1]庚烷(6d)和5,6-外-环氧-2,2-双(苄氧基)-7-氧杂双环[2.2.1]庚烷(图6e),得到从环氧化物的开环所产生的次要产物和σ键C的1,2-移位(3)-C(4)和主要产品(25,29从一个甲氧基的1,3-移位而引起)和分别为苄氧基。在相似的条件下,5