1,<i>n</i>-Rearrangement of Allylic Alcohols Promoted by Hot Water: Application to the Synthesis of Navenone B, a Polyene Natural Product
作者:Pei-Fang Li、Heng-Lu Wang、Jin Qu
DOI:10.1021/jo5004086
日期:2014.5.2
n-rearrangement (n = 3, 5, 7, 9) of allylic alcohols. In some cases, the rearrangement reactions joined isolated C–C double or triple bonds to generate conjugated polyene or enyne structure motifs. We used the 1,3-rearrangement reaction of an allylic alcohol in hot water as part of an attractive new strategy for construction of the polyene naturalproduct navenone B by iterative use of a Grignard reaction
Synthesis of New 3-(-2-Alkenyl)-2-hydroxy-5-methoxy-<i>p</i>-benzoquinones via Claisen Rearrangement of Original 5-Methoxy-4-(2-propenyloxy)-<i>o</i>-benzoquinones
The Claisen rearrangement is extended to compounds containing the benzoquinone moiety, obtained by regioselective nucleophilic substitution on 4-(p-methoxyphenoxy)-5-methoxy-o-benzoquinone (1). In the most general case, 5-methoxy-4-(2-propenyloxy)-o-benzoquinones 3 rearrange quantitatively into (E)-3-(2-alkenyl-2-hydroxy-5-methoxy-p-benzoquinones 4. Furfuryl or (2-thienyl)methyl ethers isomerize to 3-(2-methyl-3-furyl)- and 3-(2-methyl-3-thienyl)-2-hydroxy-5-methoxy-p-benzoquinones. This new synthetic method provides an efficient route to new hydroxybenzoquinones closely related to natural compounds. Thus, dihydroardisiaquinone A is synthesized in 5 steps from p-methoxyphenol.