mitsunobu reaction

 Using a mixture of toluene and THF, in this case 3:2 at 0.3 M concentration with respect to substrate made the reaction very fast, even at 0 C.  when in THF only, took 2 days, but with toluene too it took 2 hours.

TLC in these systems can be horrible due to O=PPh3's promiscuity on TLC

 First form the complex between PPh3 and DIAD (or DEAD) at 0 °C in THF; separately you mix the nucleophile and the substrate in the right solvent and once the complex PPh3-DIAD is formed (pale yellow milky colored suspension) you pour it into the other solution

Use DEAD instead of DIAD as the reagent is orders of magnitude faster, you may need to run the reactions at -20 to avoid decomposition. Use of a smaller phosphine nucleophile also helps with the reaction rate, consider PBu3 or P(OEt)3.

Use a stain to visualise the products by TLC, KMnO4 should be reliable and ought to stain any alkyne containing spots rapidly, potentially without heating.

Use good quality reagents of DIED AND PPh3 and reaction must be in anhydrous and inert conditions. 

Using anhydrous THF and fresh DIAD is important to speed up the reaction.

I have found that a mixture THF/toluene 1:1is also a nice trick to reduce your reaction time