Novel Base-Promoted Rearrangement of 2-(4-Cyano-, 2-Nitro-, and 4-Nitrobenzyloxy)tropones and 2-(2-Oxo-2-phenethyloxy)tropone to 2-[(4-Cyano-, 2-Nitro-, and 4-Nitrophenyl)hydroxymethyl]tropones and 2-(1-Hydroxy-2-oxo-2-phenethyl)tropone
Synthetic Photochemistry. XXXIX. Sensitized-Photooxygenation of 2-Benzyltropone, 2-[Hydroxy(4-nitrophenyl)methyl]tropone, and 2-(1-Hydroxy-2-oxo-2-phenylethyl)tropone. A Quenching Effect of Hydroxyl Group in the Vicinity of the Reaction Site
作者:Akira Mori、Hiroshi Suizu、Hitoshi Takeshita
DOI:10.1246/bcsj.60.3817
日期:1987.10
Singlet-oxygen oxidation of 2-[hydroxy(4-nitrophenyl)methyl]tropone gave 6,7-dioxabicyclo[3.2.2]nona-3,8-dien-2-one derivatives in good yields. A change of regioselectivity of the oxygenation with a remarkable rate of enhancement (23 times) in deuteriomethanol vs. methanol could be best explained in terms of the quenching of singlet oxygen by the free hydroxyl group in the vicinity of the reaction
Novel Base-Promoted Rearrangement of 2-(4-Cyano-, 2-Nitro-, and 4-Nitrobenzyloxy)tropones and 2-(2-Oxo-2-phenethyloxy)tropone to 2-[(4-Cyano-, 2-Nitro-, and 4-Nitrophenyl)hydroxymethyl]tropones and 2-(1-Hydroxy-2-oxo-2-phenethyl)tropone
作者:Hitoshi Takeshita、Akira Mori、Hiroshi Suizu
DOI:10.1246/bcsj.60.1429
日期:1987.4
The base-catalyzed rearrangement of 2-(2-nitro-, 4-nitro-, and 4-cyanobenzyloxy)tropones smoothly yielded corresponding 2-[(aryl)hydroxymethyl]tropones, while their thermolysis gave 3-(arylmethyl)tropolones. This reaction has no precedent analogy in troponoid chemistry, and this rearrangement is widely applicable to the 2-troponyl ethers of alcohols carrying an electron-attractive substituent on the α-position, as was verified by the occurrence of 2-(1-hydroxy-2-oxo-2-phenethyl)tropone from 2-(2-oxo-2-phenethyloxy)tropone.