Potassium Hydroxide → 4,4-Diethyl-6-ethynyl-3,4-dihydro-2H-1-benzothiopyran

Reaction equation

[OH-].[K+].[CH2:3]([C:5]1([CH2:21][CH3:22])[C:14]2[C:9](=[CH:10][CH:11]=[C:12]([C:15]#[C:16][Si](C)(C)C)[CH:13]=2)[S:8][CH2:7][CH2:6]1)[CH3:4]>O.C(O)C>[CH2:21]([C:5]1([CH2:3][CH3:4])[C:14]2[C:9](=[CH:10][CH:11]=[C:12]([C:15]#[CH:16])[CH:13]=2)[S:8][CH2:7][CH2:6]1)[CH3:22]

Participants

Procedure

A solution of 2.21 g (39 mmol) of potassium hydroxide in 2.0 mL of water and 20.0 mL of ethanol was added to 1.49 g (4.93 mmol) of (4,4-diethylthiochroman-6-yl)(trimethylsilyl)acetylene (Compound 26) and the resulting mixture stirred at room temperature for 5 hours during which time it became homogeneous. The solvent was removed in-vacuo and the residue was acidified with 5% aqueous H2SO4. The product was extracted with 2×50 mL of ether.