The influence of distal substitution on the base-induced isomerization of long-chain terminal alkynes

•A distal isobranch in a long-chain terminal alkyne influences the rate of isomerization.•Alkyne 9 isomerizes 2.1 times faster than alkyne 5 at 55°C.•The distal isobranch disrupts the coiling to allow more rapid deprotonation.•Simple energy calculations indicated that coiled 9 was about 2.4kJ higher in energy.•The DMSO contained 4.38% of water.