Asymmetric synthesis of isomerically pure allenyl boranes from alkynyl boranes through a 1,2-insertion-1,3-borotropic rearrangement
Asymmetric synthesis of isomerically pure allenyl boranes from alkynyl boranes through a 1,2-insertion-1,3-borotropic rearrangement
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DOI：
10.1002/anie.200603467
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发表时间：
2007-01-01
影响因子：
16.6
通讯作者：
Soderquist, John A.
中科院分区：
文献类型：
--
作者：
Canales, Eda;Gonzalez, Ana Z.;Soderquist, John A.
最近，我们描述了多种新的10-三甲基甲硅烷基-9-硼双环[3.3。 2] 癸烷 (10-TMS-9-BBD) 试剂，用于醛的不对称烯丙基-、巴豆基-、丙二烯基-和炔丙基硼化。[1]这些刚性且坚固的三烷基硼烷系统通过调整已知的有机硼烷转化而制备，具有异常稳定和选择性。此外，相关的 10-Ph-9-BBD 试剂也可以很容易地制备，这些试剂对于酮和酮亚胺的相关加成反应非常有效。 [2]简单的格氏程序可用于制备许多此类试剂，包括 B-炔基 10-TMS-9-BBD (2)，其与 N-酰基醛亚胺的不对称迈克尔加成提供非外消旋 N-炔丙基酰胺。[3]在 2 建模研究的基础上，我们设想将 TMSCHN2 高度立体选择性插入 2 的炔基 BÀC 键中，通过 3 得到 4（方案 1）。反围平面 1, 2-
Very recently, we described a variety of new 10-trimethylsilyl-9-borabicyclo [3.3. 2] decane (10-TMS-9-BBD) reagents for the asymmetric allyl-, crotyl-, allenyl-, and propargylboration of aldehydes.[1] Prepared through adaptations of known organoborane transformations, these rigid and robust trialkyl borane systems are exceptionally stable and selective. Moreover, the related 10-Ph-9-BBD reagents, which are quite effective for the related addition reactions to ketones and ketimines, can also be prepared readily.[2]Simple Grignard procedures can be used to prepare many of these reagents, including the B-alkynyl 10-TMS-9-BBDs (2), the asymmetric Michael addition of which to N-acyl aldimines provides nonracemic N-propargyl amides.[3] On the basis of modeling studies with 2, we envisaged the highly stereoselective insertion of TMSCHN2 into the alkynyl BÀC bond of 2 to give 4 via 3 (Scheme 1). An antiperiplanar 1, 2-