The rearrangement of 1,5-hexadiyne and 1,6-heptadiyne
作者:D.A. Ben-Efraim、F. Sondheimer
DOI:10.1016/0040-4020(69)80027-x
日期:1969.1
The rearrangement of 1,5-hexadiyne (I) with potassium t-butoxide in t-butyl alcohol led mainly to a ca. 2:1 mixture of cis-1,3-hexadien-5-yne (IVa) and trans-1,3-hexadien-5-yne (IVb), and a minor amount of 2,4-hexadiyne (II). Both IVa and IVb were isolated and characterized. Contrary to previous reports, a similar result was obtained when the rearrangement of I was carried out with ethanolic potassium
The thermal cycloisomerization of the 1,3-hexadiene-5-ynes 1a–e has been studied at temperatures above 500°C and reaction times of about 0.3 s (1a–d) and at a pressure of 1.5 · 10−2 Torr (FVP, 1e), respectively, at low partial pressures in quartz flow systems. While 1a and 1b cycloisomerize exclusively to the corresponding benzenes and pentafulvenes, substrates 1c–e cyclize primarily to 4-substituted