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[摘要]：The reaction of tetrahydroselenopyran-2-one with ethynyllithiums, followed by treatment with aq. 5% H2SO4 successfully led to a two-carbon ring expansion to give the 2-substituted 5,6,7,8-tetrahydroselenocin-4-ones in 43-95% yields. Seven- to nine-membered g-selena-a,b-unsatd. cyclic ketones and a 5,6,7,8-tetrahydrotellurocin-4-one were also prepd. from the corresponding selenolactones or tellurolactone in a one-pot reaction. |
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