Subramaniam G., Gilpin R. K., Synthesis (BRD), (1992) N 12, S 1232-1234
作者:Subramaniam G., Gilpin R. K.
DOI:——
日期:——
A Convenient Synthesis of 2′,3′′′′-Dimethyl-<i>p</i>-sexiphenyl
作者:G. Subramaniam、R. K. Gilpin
DOI:10.1055/s-1992-35683
日期:——
Hitherto unreported 2′,3′′′′-dimethyl-p-sexiphenyl (6) is synthesized by an unambiguous route in good yield, starting from inexpensive commercially available biphenyl. The general reaction sequence consists of: (i) bischloromethylation of biphenyl, to give 4,4′-bis(chloromethyl)biphenyl (1) (ii) conversion of 1, to its bisphosphonium salt 2 (iii) a Wittig reaction of the salt with two equivalents of β-methylcinnamaldehyde to yield hitherto unreported 4,4′-bis(3-methyl-4-phenyl-buta-1,3-dienyl)biphenyl (3) (iv) the [4 + 2] cycloaddition of 3 with diethyl acetylenedicarboxylate to yield 4 (v) hydrolysis of 4 to 5 (vi) and oxidative decarboxylation of 5 with potassium hexacyano ferrate(III). All reactions which are simple and straightforward proceed in good yield, except the last step.