Microwave-mediated Claisen rearrangement followed by phenol oxidation: a simple route to naturally occurring 1,4-benzoquinones. The first syntheses of verapliquinones A and B and panicein A.
The naturally occurring 1,4-benzoquinones 2-methoxy-6-propyl-1,4-benzoquinone (1), 2-methoxy-6-pentyl-1,4-benzoquinone (primin 2), 2-methoxy-6-pentadecyl-1,4-benzoquinone (3), 2-methoxy-6-heptadecyl-1,4-benzoquinone (dihydroirisquinone, pallasone B; 4) were synthesized by a simple protocol involving microwave accelerated Claisen rearrangement of allyl ethers 10, followed by hydrogenation of the side chain alkene, and oxidation to the quinone. The Claisen-based methodology was extended to the first synthesis of the marine benzoquinones verapliquinones A and B (5 and 6), and panicein A (7). Isoarnebifuranone (9) was also synthesized by a similar strategy.
Davis
Christopher J
CJ
Department of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, United Kingdom.
Hurst
Timothy E
TE
Jacob
Aouregan M
AM
Moody
Christopher J
CJ
D016227:Benzoquinones / Q000138:chemical synthesis* / Q000737:chemistry; D001685:Biological Factors / Q000138:chemical synthesis* / Q000737:chemistry; D020650:Combinatorial Chemistry Techniques; D005658:Fungi / Q000737:chemistry; D008872:Microwaves; D015394:Molecular Structure; D010084:Oxidation-Reduction; D010636:Phenols / Q000737:chemistry*; D010946:Plants, Medicinal / Q000737:chemistry
D016227:Benzoquinones; D001685:Biological Factors; D010636:Phenols; C501273:panicein A; C501271:verapliquinone A; C501272:verapliquinone B