Reaction pathway of conjugate addition of lithium organozincates to s-trans-enones.
Reaction pathway of conjugate addition of lithium organozincates to s-trans-enones.
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DOI：
10.1021/ja070123k
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发表时间：
2007-10
影响因子：
15
通讯作者：
M. Uchiyama;Shinji Nakamura;Taniyuki Furuyama;E. Nakamura;K. Morokuma
中科院分区：
文献类型：
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作者：
M. Uchiyama;Shinji Nakamura;Taniyuki Furuyama;E. Nakamura;K. Morokuma
用密度泛函理论(DFT)方法研究了有机锌与甲基乙烯基酮(MVK)的1，4-加成反应机理。对Me_3ZnLi与(MeLi)_2加成反应的考察表明，α，β-不饱和羰基化合物的精确过渡态结构决定了反应的选择性。在有机锌盐的情况下，1，4-加成反应通过开放形式的TS顺利进行，而烷基锂通过闭合TS进行1，2-加成反应。这种锌酸盐的1，4-加成反应不涉及电子转移过程，不同于发生铜原子氧化/还原的有机铜酸盐反应。
Density functional theory (DFT) calculations were performed to understand the reaction mechanism of organozincates in 1,4-addition to methyl vinyl ketone (MVK). Examination of the addition of Me3ZnLi to MVK as compared with that of (MeLi)2 showed that the precise transition state structures critically determine the reaction selectivity for α,β-unsaturated carbonyl compounds. In the case of organozincates, the 1,4-addition proceeds smoothly through an open form TS, whereas alkyllithiums favor 1,2-addition through a closed TS. This 1,4-addition mechanism of Zn-ates does not involve an electron transfer process and is different from the reaction of organocuprates, in which oxidation/reduction of the copper atom occurs.