In benzene, 2 hr., room temperature unless otherwise indicated. R= 4-t-Bu; R'= Et. Analysis by gas chromatography with internal standard. Apportionment, by column chromatography. d R= cholestane residue; R'= Et. Analysis by column chromatography. Reaction time 24 hr. e R= 4-t-Bu; R'= n-Pr. Analysis by isolation and gas chromatography. f Toluene distilled from catalyst prior to reaction. Analysis by column chromatography. g Et, hanol added to ...