Mycophenolicacid (28) has been obtained by a convergent synthesis starting from methyl 6-bromo-4-methylhex-4-enoate (13) and 5,7-dihydroxy-4-methylphthalide (24). For the total synthesis of 5,7-dihydroxy-4-methylphthalide, 1-carbethoxy-2,3-dimethylcyclohexa-4,6-dione (14) was aromatized and transformed into 4,6-dimethoxy-2,3-dimethylbenzamide. The photolysis of the corresponding N-chloroamide and
Iodine(III)-mediated halogenations of acyclic monoterpenoids
作者:Laure Peilleron、Tatyana D Grayfer、Joëlle Dubois、Robert H Dodd、Kevin Cariou
DOI:10.3762/bjoc.14.96
日期:——
Five different halofunctionalizations of acyclic monoterpenoids were performed using a combination of a hypervalent iodine(III) reagent and a halide salt. In this manner, the dibromination, the bromo(trifluoro)acetoxylation, the bromohydroxylation, the iodo(trifluoro)acetoxylation or the ene-type chlorination of the distal trisubstituted double bond occurred with excellent selectivity and moderate
Chemodivergent, Tunable, and Selective Iodine(III)-Mediated Bromo-Functionalizations of Polyprenoids
作者:Tatyana D. Grayfer、Pascal Retailleau、Robert H. Dodd、Joëlle Dubois、Kevin Cariou
DOI:10.1021/acs.orglett.7b02125
日期:2017.9.15
Mild oxidation of bromides by iodine(III) reagents generated active electrophilic bromination species that were reacted with polyprenoids. By simple and minor variations of an I(III)/Br combination, the reactivity could be selectively steered toward dibromination, oxybromination, or bromocyclization, giving access to a wide array of brominated motifs.
Synthesis of (±)-karahana ether and karahanaenone by selective cyclization of 6,7-epoxygeranyl acetate
作者:Alejandro F. Barrero、Enrique J. Alvarez-Manzaneda、P.Linares Palomino
DOI:10.1016/s0040-4020(01)89332-7
日期:1994.1
Efficient methods for preparing (±)-karahanaether (1b) and karahanaenine (2) from 6,7-epoxygeranyl acetate(3), by Lewis-acid-catalyzed electrophillic cyclization, are described.
Epoxy terpenes cyclize readily, by confinement within zeolite NaY, to form exomethylenic cyclohexanols as the major products. The selective monocyclization of 10,11-epoxyfarnesyl acetate within NaY provides a short and efficient biomimetic route to (+/-)-elengasidiol and (+/-)-farnesiferols B-D.