The Homoconjugated Electron-Releasing Carbonyl Group of 1-Methylbicyclo[2.2.1]Hept-5-En-2-One - Regioselective Syntheses of 5-Chloro-1-Methylbicyclo[2.2.1]Hept-5-En-2-One and 6-Chloro-1-Methylbicyclo[2.2.1]Hept-5-En-2-One
Syntheses of (+/-)-2-exo-cyano-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-endo-yl acetate (1) and of (+/-)-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (2) are reported. The additon of PhSeCl to 1 afforded (+/-)-5-endo-chloro-2-exo-cyano-1-methyl-6-exo-(phenylselenenyl)-7-oxabi cyclo[2.2.1]hept-2-endo-yl acetate (6), whereas 2 added to PhSeCl with the opposite regioselectivity giving (+/-)-6-endo-chloro-1-methyl-5-exo-(phenylselenenyl)-7-oxabicyclo[2.2.1] heptan-2-one (7). These adducts were converted into 5-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (9) and 6-chloro-1-methyl-7-oxabicyclo[2.2.1]hept-5-en-2-one (10), respectively.
1993
76
6
2338
2343
Univ lausanne,chim sect,rue la barre 2,ch-1005 lausanne,switzerland.
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