Phosphorus pentachloride → Spiro[cyclobutane-1,2'-thiochroman]-4'-one
Reaction equation
[C:1]1([S:7][C:8]2([CH2:12][C:13]([OH:15])=O)[CH2:11][CH2:10][CH2:9]2)[CH:6]=[CH:5][CH:4]=[CH:3][CH:2]=1.P(Cl)(Cl)(Cl)(Cl)Cl>C1C=CC=CC=1>[O:15]=[C:13]1[C:6]2[CH:5]=[CH:4][CH:3]=[CH:2][C:1]=2[S:7][C:8]2([CH2:9][CH2:10][CH2:11]2)[CH2:12]1Participants
4
Reactant 2
Product 1
Reagents, catalysts & solvents 1
Procedure
A solution of 1-Phenylthiocyclobutane-1-acetic acid (10 mmol) in benzene was treated with excess of PCl5 at room temperature for 15 h. The reaction mixture was concentrated under vacuum and the residue was again dissolved in benzene. AlCl3 was then added to the solution and it was stirred for 24 h at room temperature. The reaction mixture was diluted with excess of ethyl acetate and washed with water and brine. Organic layer was then separated, dried over anhydrous Na2SO4 and concentrated under vacuum. The residue was purified by column chromatography to afford the desired compound as oil.