1.5- Hexadiyne, oxidative coupling

A. Oxidative coupling of 1,5-hexadiyne. A 12-1., four-neeked, round-bottomed flask provided with a stopcock at the bottom (Figure 1) (Note 1) is fitted with a stirrer (Note 2), a reflux condenser, and a 500-ml. dropping funnel equipped with a pressure-equalizing side arm. The... 

Oxidative Coupling or Propargvl Alcohol Preparation of 2,4-Hexadiyn-l,6-diol... 

Oxidative coupling of 1,5-hexadiyne to cyclooctadeca-l,3,7,9,l3,I5-liexaytte, A 6-1. three-necked, round-bottomed flask fitted with a stirrer having two 7.5-cm. paddles 9 cm. apart, a reflux condenser, and a 50O-ml. dropping funnel (with a pressure equalizing arm) is charged with 600 g. of cupric acetate monohydrate and 3.81. of... 

Oxidative coupling of 1,5-hexadiyne (150) with copper(ii) acetate in pyridine yielded a mixture of the cyclic trimer 151, the tetramer 152, the pentamer 153 and the hexamer 154 in addition to other compounds - The cyclic trimer 151... 

Wolovsky describes the oxidative coupling of 1,5-hexadiyne, followed by prototropic rearrangement by heating with potassium /-butoxide in f-butanol-benzene at 100°. The resulting mixture of unsaturated hydrocarbons was easily separated by elution chromatography on a column of alumina impregnated with 20% silver nitrate into the tetradehydro[18]annulene (111) and the two isomeric tridehydro[18]annulenes (1) and (11). 

The four structures are possible because the two cis/trans butadiene units can each be incorporated into the ring in two ways. This degeneracy is inherent in the preparation by oxidative coupling of 1,5-hexadiyne and subsequent pro-totropic rearrangement... 

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