1-(4-methoxyphenoxycarbonyloxy)-5-(4-methoxybenzyloxy)-4,4-dimethyl-2-pentyne

1-methoxycarbonyloxy-5-(4-methoxybenzyloxy)-4,4-dimethyl-1-phenyl-2-pentyne

1-methoxycarbonyloxy-5-(4-methoxybenzyloxy)-1,4,4-trimethyl-2-pentyne