Synthesis of Δ7-1-methylbicyclo[5,4,0]undecene-2,9-dione and its condensation with acetylene
作者:R. Selvarajan、J.P. John、K.V. Narayanan、S. Swaminathan
DOI:10.1016/0040-4020(66)80069-8
日期:1966.1
2-methylcycloheptane-1,3-dione (II) obtained by methylation of cycloheptane-1,3-dione furnishes 2-methyl-2(3′-oxobutyl) cycloheptane-1,3-dione (III) which is cyclized and dehydrated in a single step to afford the title compound (Ic) in the presence of a mixture of pyrrolidine and acetic acid. A by-product isolated in this cyclization is the bridged ketol VII. Treatment of III with p-toluenesulphonic acid gives
通过将环庚烷-1,3-二酮甲基化而将甲基乙烯基酮迈克尔加成到2-甲基环庚烷-1,3-二酮(II)中,可得到2-甲基-2(3'-氧丁基)环庚烷-1,3-二酮(III)在吡咯烷和乙酸的混合物存在下,将其一步一步地环化和脱水,得到标题化合物(Ic)。在该环化中分离出的副产物是桥接的酮醇VII。用对甲苯磺酸处理III,主要得到酸IV,而Ic的收率很低。Ic与乙炔锂的反应提供了意料不到的产物IX。给出了对相似的二酮Ia,Ib和Ic的不同乙炔基化过程的解释。