Helvetica Chimica Acta p. 1703 - 1720 (1987)
Update date:2022-07-31
Topics:
Drian, Claude Le
Vogel, Pierre
In the presence of HSO3F/Ac2O in CH2Cl2, 2-exo- and 2-endo-cyano-5,6-exo-epoxy-7-bicyclo<2.2.1>hept-2-yl acetates (6a,b) gave products derived from the epoxide-ring opening and a 1,2-shift of the unsubstituted alkyl group (? 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 (6d) and of 5,6-exo-epoxy-2,2-bis(benzyloxy)-7-oxabicyclo<2.2.1>heptane (6c) gave minor products arising from epoxide ring opening and the 1,2-shift of ? bond C(3)-C(4) and major products (25,29) arising from the 1,3-shift of a methoxy and benzyloxy group, respectively.Under similar conditions, 5,6-exo-epoxy-2,2-ethylenedioxy-7-oxabicyclo<2.2.2>heptane (6f) gave 1,1-(ethylenedioxy)-2-(2-furyl)ethyl acetate (32, major) and a minor product 33 arising from the 1,2-shift of ? bond C(3)-C(4).The following order of migratory aptitudes for 1,2-shifts toward electron-deficient centers has been established: acyl > alkyl > alkyl α-substituted with inductive electron-withdrawing groups.This order is valid for,competitive Wagner-Meerwein rearrangements involving equilibria between carbocation intermediates with similar exothermicites.
View Morewebsite:http://www.cheminn.com/
Contact:86-531-67875205
Address:No.9-2,South of Shanda Road, Jinan ,China
Chengdu King-tiger Pharm-chem. Tech. Co., Ltd
Contact:028-85317716
Address:Tianfu Life Science Park, No. 88 South Keyuan Road, Gaoxin District, Chengdu City, Sichuan Province, PRC.
website:http://www.angchenchem.com
Contact:+86-510-88302099 82327577
Address:Rm. 404/405, Floor 4th, No. 983 FengXiang Road, Wuxi, China
website:http://www.oceanchem-group.com
Contact:86-536-8596048
Address:9th floor,Building B future Plaza, No.88.Fenghuang Street,Weifang,Shandong,China
website:http://www.cheminn.com/
Contact:86-531-67875205
Address:No.9-2,South of Shanda Road, Jinan ,China
Doi:10.1021/jm00111a006
(1991)Doi:10.1039/c39880000423
(1988)Doi:10.1016/0022-328X(85)87195-3
(1985)Doi:10.1016/S0040-4020(01)86906-4
(1987)Doi:10.1021/jm00117a026
(1988)Doi:10.1246/bcsj.60.3405
(1987)