Hey there Jack,
Olivetol (5-Pentyl-1,3-benzenediol) is a simple organic aromatic and I would advise you to look at ANY introductory organic chemistry text to find your answer as there are MANY was to synthesize this! But as you indicated in the chemical name you gave Olivetol is a derivative of alpha-resorcyclic acid and the easiest synthesis with the fewest steps and time that I have found so far is as follows:
1) Reflux a-resorcyclic acid, K2CO3, benzyl chloride in DMF (1:6:6) with stirring for 12 hr, dilute with cold water, extract with ether, evap, crystallize from benzene-hexane.
2) Reduce with LiAlH4 (1:16.7) in DRY ether, decomp with 5% HCl, evap solvent, crystalize from benzene-hexane.
3) Add to PCC, NaAc in DRY DCM (stirring), 1 hr, dil. with DRY ether, decant DCM-ether, wash with ether and decant, pass total org layer through silica column, evap solvent, crystallize from benzene-hexane.
4) Add to BuMgBr in DRY ether (stirring, N2, 0 deg. C), 2 hr, decomp with 5% H2SO4. Collect org layer, extract aq layer with ether, wash combined org layers with brine, evap, crystallize from acetone-benzene.
5) Reflux with p-toluenesulfonic acid in benzene (Dean Stark), wash with NaHCO3, brine, evap, dissolved in EtOH, hydrogenate with 10% Pd/C, filter, evap, dist under reduced pressure.
My acknowledgment to Anand C. et al for there excellent work to produce a facile method. There is a 3 step method that is MUCH easier ^^ but it requires non-3-en-2-one and some other atypical supplies whereas this method is slightly longer but ANY respectable laboratory will have the nessecary chemicals ^^ and will likely have the starting acid (the synthesis of which can be realized from benzoic acid and is so trivial I wouldn't bother mentioning it)
As for budullewraagh's comment. I proclaim that I in no way condone the use of my posted information as a conduit for THC procurement. Although, budullewraagh should know that Olivetol is a very handy synthetic starting material for vast number or published syntheses, THC synthesis itself is a stimulating and non-trivial synthesis in it self, and most importantly that while Olivetol is a THC precursor it is the delta9 and delta8 (there are actual 4 isomers but I can't remember the other two ) that provide the physiological affect we call 'high' but many other cannabinoids can be made from Olivetol (cannabidiol to name one) that are present in organic extracts from Cannabis sativa that not only act to suppress the affects of the delta9 variety but have been reported to have neuroprotective, neuroregenetive, antiolytic and antipsycotic properties too.
One that note I too hope this post doesn't get me in trouble from the admin and in hindsight lol does anyone else find it ironic that Jackknife used the internet to voice his ignorance whereas he could have used that same tool to find the answer I gave him? lolz. Take a look next time dude!
adarkervision