Oxidn. of 12 RR1CHCH(CO2Et)2 [R = (un)substituted Ph, R1 = H, Me] by Mn(OAc)3 in AcOH2, Ce(NH4)2(NO)6 in MeOH, or Fe(CHO4)3 in MeCN in the presence of 19 R2R3C:CHR4 [R2 = H, alkyl, alkenyl, Ph, AcO, EtO2C, cyano, etc.; R3 = H, Me3CCH2, Me, EtO2C, EtO2CCH:CH; R4 = H, Me, EtO2C; R2R4 = (CH2)4, CH:CHCH2] was studied. The results are consistent with a common mechanism involving selective generation of malonyl radicals from high-valent metal malonyl complexes, their addn. to the olefin, and competition of the adduct radical between intramol. cyclization to produce highly functionalized tetrahydronaphthalenes I (XC6H4 = R) and oxidn. by metal salt to give mainly γ-lactones II. Several electron-withdrawing and -releasing substituents on the arom. ring and on the olefin can be successfully used in the synthesis of I without olefin telomerization. The influence of metal and olefin or arom. substituents on the homolytic addn. and intramol. arom. substitution is discussed
Synthesis of substituted tetrahydronaphthalenes by manganese(III), cerium(IV), and iron(III) oxidation of substituted diethyl .alpha.-benzylmalonates in the presence of olefins
CITTERIO, ATTILIO;SEBASTIANO, ROBERTO;MARION, ANTONIO PIO MARIA;
1991-01-01
Abstract
Oxidn. of 12 RR1CHCH(CO2Et)2 [R = (un)substituted Ph, R1 = H, Me] by Mn(OAc)3 in AcOH2, Ce(NH4)2(NO)6 in MeOH, or Fe(CHO4)3 in MeCN in the presence of 19 R2R3C:CHR4 [R2 = H, alkyl, alkenyl, Ph, AcO, EtO2C, cyano, etc.; R3 = H, Me3CCH2, Me, EtO2C, EtO2CCH:CH; R4 = H, Me, EtO2C; R2R4 = (CH2)4, CH:CHCH2] was studied. The results are consistent with a common mechanism involving selective generation of malonyl radicals from high-valent metal malonyl complexes, their addn. to the olefin, and competition of the adduct radical between intramol. cyclization to produce highly functionalized tetrahydronaphthalenes I (XC6H4 = R) and oxidn. by metal salt to give mainly γ-lactones II. Several electron-withdrawing and -releasing substituents on the arom. ring and on the olefin can be successfully used in the synthesis of I without olefin telomerization. The influence of metal and olefin or arom. substituents on the homolytic addn. and intramol. arom. substitution is discussedFile | Dimensione | Formato | |
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