General procedure. The propargylic sulfinate was dissolved in the solvent (0.05 M). The copper catalyst was added in one portion.
The mixture was stirred at room temperature and the reaction was monitored by TLC. Upon complete conversion to the product (or one week reaction time), the catalyst was removed by filtration (using a Sterilite nylon membrane (0.2 lm, 47 mm) for the zeolite catalyst, or through a short pad of Celite for the copper salts) and rinsed with dichloromethane. The zeolite catalyst was dried by aspiration and then recovered by carefully scraping it from the membrane; traces remain adsorbed to the membrane and prevent complete recovery. The filtrate was concentrated on a rotary evaporator
and trace solvent removed by high vacuum pump to yield the allenic sulfone.