Application of the Lithiation-Borylation Reaction to the Preparation of Enantioenriched Allylic Boron Reagents and Subsequent In Situ Conversion into 1,2,4-Trisubstituted Homoallylic Alcohols with Complete Control over All Elements of Stereochemistry
Application of the Lithiation-Borylation Reaction to the Preparation of Enantioenriched Allylic Boron Reagents and Subsequent In Situ Conversion into 1,2,4-Trisubstituted Homoallylic Alcohols with Complete Control over All Elements of Stereochemistry
复制标题
DOI：
10.1021/ja910593w
复制
发表时间：
2010-03-24
影响因子：
15
通讯作者：
Aggarwal, Varinder K.
中科院分区：
文献类型：
--
作者：
Althaus, Martin;Mahmood, Adeem;Aggarwal, Varinder K.
Hoppe 的锂化氨基甲酸酯与乙烯基硼烷和硼酸酯的反应生成烯丙硼烷/硼酸酯，随后添加醛提供了一条新途径，制备具有高对映体比率和非对映体比率的对映体富集的高烯丙醇。具体来说，金雀花碱络合的锂化氨基甲酸酯与反式烯基-9-BBN衍生物反应，然后添加醛，得到大于95:5 er和99:1 dr的(2)-反高烯丙醇。然而，在甲基取代的氨基甲酸锂的特殊情况下，需要无二胺条件才能实现高选择性。金雀花络合的锂化氨基甲酸酯与(Z)-烯基频哪醇硼酸酯和(E)-烯基新戊基硼酸酯的反应分别以大于96:4 er和98:2 dr的方式产生(E)-顺式醇和(E)-反高烯丙醇。在这些反应中，需要路易斯酸（MgBr2 或 BF3 中心点 OEt2）来促进 1,2-金属化物重排以及中间体烯丙硼酸酯向醛的加成。该方法为高选择性地制备三类高烯丙醇中的每一种提供了通用途径。
The reactions of Hoppe's lithiated carbamates with vinylboranes and boronic esters give allylic boranes/boronic esters, and subsequent addition of aldehydes provides a new route to enantioenriched homoallylic alcohols with high enantiomeric ratios and diastereomeric ratios. Specifically, reactions of sparteine-complexed lithiated carbamates with trans-alkenyl-9-BBN derivatives followed by addition of aldehydes gave (2)-anti-homoallylic alcohols in greater than 95:5 er and 99:1 dr. However, in the special case of the methyl-substituted lithiated carbamate, diamine-free conditions were required to achieve high selectivity. Reactions of sparteine-complexed lithiated carbamates with (Z)-alkenyl pinacol boronic esters and (E)-alkenyl neopentyl boronic esters gave (E)-syn- and (E)-anti-homoallylic alcohols, respectively, in greater than 96:4 er and 98:2 dr. In these reactions, a Lewis acid (MgBr2 or BF3 center dot OEt2) was required to promote both the 1,2-metalate rearrangement and the addition of the intermediate allylic boronic ester to the aldehyde. This methodology provides a general route to each of the three classes of homoallylic alcohols with high selectivity.