Cyclopent startg

Cyclopent-2-enone ring. A mixture of startg. iodonium salt and K-/cr/-butoxide allowed to react in tetrahydrofuran at — 78° until reaction complete product. Y 61 %. The formation of the bicyclic compd. can be explained by regioselective 1,5-carbon-hydrogen insertion of the alkylidenecarbene intermediate. F.e.s. M. Ochiai et al., J Am. Chem. Soc. 110, 6565-6 (1988). 

A soln. of dry n-propyltriphenylphosphonium bromide in dimethyl sulfoxide treated at room temp, under Ng with methylsulfinyl carbanion prepared from NaH and dimethyl sulfoxide, after 5 min. the startg. hemiacetal in dimethyl sulfoxide added, and stirred 2.5 hrs. at room temp. 2-(cf -2-pentenyl)cyclopent-3-en-l-ol. Y 70%. P.A.Grieco, J. Org. Chem. 57, 2363 (1972). 

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