摘要：

We were faced recently with the task of preparing either or both of the olefins 1 and 2 with deuterium incorporation as completely regiospecific as possible. The highly specific syn addition of alkylcopper reagents to 1-alkynes1,2,3 appeared the simplest and most direct route to these substances. However, untilthe recent publication of Helquist,3 the addition of methyl in such a fashion, while of obvious synthetic importance had been

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