A Concise and Convenient Synthesis of DL-proto-Quercitol and DL-gala-Quercitol via Ene Reaction of Singlet Oxygen Combined with [2 + 4] Cycloaddition to Cyclohexadiene.
Photooxygenation of 1,4-cyclohexadiene afforded hydroperoxy endoperoxides 3 and 4 in a ratio of 88:12. Reduction of 3 with LiAlH(4) or thiourea followed by acetylation of the hydroxyl group and KMnO(4) oxidation of the double bond gave proto-quercitol 10b. Application of the same reaction sequences to 4 resulted in the formation of gala-quercitol 14. Quercitols were easily obtained by ammonolysis of acetate derivatives in MeOH. The outcome of dihydroxylation reactions were supported by conformational analysis.
Salamci
Emine
E
Department of Chemistry, Faculty of Arts and Sciences, Atatürk University, 25240-Erzurum, Turkey.
Seçen
Hasan
H
Sütbeyaz
Yasar
Y
Balci
Metin
M