Be careful to use the correct amount of reaction reagent. Today I use Red-Al to convert alkyne to alkene. The concentration of it was 65% by weight in toluene. However I use it as pure one mistakely. As a result, the amount of Red-Al I added to my reaction was not enough and the reaction did not work well. Fortunately, the reaction is just in small scale. Otherwise, the lost will be terribly huge.