作者:Kuniyuki Takahashi、Go Hata、Akihisa Miyake
DOI:10.1246/bcsj.46.600
日期:1973.2
tail-to-tail dimerization almost selectively, while the addition of a large amount of phenol (phenol/isoprene=1/1.5) afforded head-to-head dimers (2-vinyl-5-methyl-1,6-heptadiene and 3,6-dimethyl-1,cis-3,7-octatriene) as main dimers (more than 40% of all the dimers). In a 1:3 ratio of phenol to isoprene the dimers consisted of mainly 2,6-dimethyl-1,trans-3,7-octatriene derived from a head-to-tail dimerization
研究了 PdBr2(Ph2PCH2CH2PPh2)2-PhONa 催化剂催化异戊二烯的低聚反应。苯酚的加入大大提高了催化剂的活性。鉴定了五个线性二聚体。苯酚与异戊二烯的摩尔比显着影响异构二聚体的分布。在少量苯酚(苯酚/异戊二烯 = 1/30)存在下的反应几乎选择性地从尾对尾二聚反应中得到 2,7-二甲基-1,反式-3,7-辛三烯,而添加大量苯酚(苯酚/异戊二烯=1/1.5)得到头对头二聚体(2-乙烯基-5-甲基-1,6-庚二烯和3,6-二甲基-1,顺-3, 7-辛三烯)作为主要二聚体(占所有二聚体的 40% 以上)。在苯酚与异戊二烯的比例为 1:3 时,二聚体主要由 2,6-二甲基-1,反式-3,7-辛三烯组成,源自头尾二聚。