Reaction Of Metallated Allenes With Phenylsulfinylamine

Lithiated allenes or allenylmagnesium bromides readily react (THF/hexane, m 90 to m 105°C, 10-15 r min) with phenylsulfinylamine to give N -phenyl-2-alkynylsulfinamides. The reaction z of metallated 3-methylbuta-1,2-diene leads to the formation of not only 2-methyl- N -phenylbut-3-yne-2-sulfinamide, but also its allenic isomer, 3-methyl- N -phenylbuta-1,2-diene-1-sulfinamide. Metallated penta-1,2-diene, 1-propa-1,2-dienylcyclohexane and 4,4-dimethylpenta-1,2-diene react with phenylsulfinylamine to form acetylenes 3 , 4 and 6 respectively as a mixture of diastereoisomers.