Transition structures for the allylboration reactions of formaldehyde by allylborane and allylboronic acid
Transition structures for the allylboration reactions of formaldehyde by allylborane and allylboronic acid
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DOI：
10.1021/ja00186a011
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发表时间：
1989-02
影响因子：
15
通讯作者：
Yi Li;K. Houk
中科院分区：
文献类型：
--
作者：
Yi Li;K. Houk
用从头算方法和3- 21 G基组计算了甲醛与烯丙基硼烷和烯丙基硼酸反应的椅式和扭船式跃迁结构。用6- 31 G ~* 基组计算了各过渡结构的相对能量。预计扭船过渡结构的稳定性比椅子低8大卡/摩尔。碳-碳键的立体控制形成在有机合成中非常重要。1近年来，烯丙基有机金属试剂对羰基化合物的加成反应得到了积极的探索，2· 3* 特别是烯丙基有机硼烷试剂的使用，已被证明是一种有价值的构建碳-碳键的方法，具有良好的立体化学控制。3™ 5
Chair and twist-boat transition structures for the reactions of formaldehyde with allylborane and allylboronic acid have been located with ab initio molecular orbital calculationsand the 3-21G basis set. The relative energies of the transition structures were evaluated with the 6-31G* basisset. The twist-boat transition structure is predicted to be 8 kcal/mol less stable than the chair.The stereocontrolled formationof carbon-carbon bonds is of great importance in organic synthesis. 1 Additions of allylic organometallic reagentsto carbonyl compounds have been actively explored in recent years, 2· 3* and the use of allylic organoborane reagents, in particular, has been shown to be a valuable method for the construction of carbon-carbon bonds with excellent control of stereochemistry. 3™ 5