Carbon-carbon bond formation with allylmagnesium chloride
Carbon-carbon bond formation with allylmagnesium chloride
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DOI：
10.1021/jo9710386
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发表时间：
1997-12-26
影响因子：
3.6
通讯作者：
Geremia, JM
中科院分区：
文献类型：
--
作者：
Taber, DF;Green, JH;Geremia, JM
制备有机化学的核心是亲核碳-碳键的形成。最常见的是，稳定阴离子（如烯醇酸盐）被用作亲核试剂。相比之下，简单的有机金属衍生物，如烷基锂和烷基卤化镁（格氏试剂）通常不能有效地取代普通卤化物或磺酸盐。这个问题已经通过使用，例如，锂二烷基铜酸盐规避。我们想提请注意这条规则的一个未被充分认识的例外，烯丙基氯化镁。我们报道，未催化的烯丙基氯化镁不仅具有亲核性，足以攻击甘油醇和它们的三烷基醚，而且还具有亲核性，足以取代伯溴化物和仲甲酰酸盐（表1）。通常，用格氏试剂打开环氧化物，包括这里描述的甘油衍生物，需要铜催化。虽然环氧化物与烯丙基氯化镁之间的亲核开度已被确认，但还没有将烯丙基氯化镁加入到甘油醇中的报道。
Preparative organic chemistry centers on nucleophilic carbon-carbon bond formation. Most commonly, stabilized anions (eg enolates) are used as nucleophiles. In contrast, simple organometal derivatives such as alkyllithiums and alkylmagnesium halides (Grignard reagents) are usually not effective for the displacements of ordinary halides or sulfonates. This problem has been circumvented by the use of, for instance, lithium dialkyl cuprates. We would like to draw attention to an underappreciated exception to this rule, allylmagnesium chloride. 2We report that uncatalyzed allylmagnesium chloride is not only nucleophilic enough to attack both glycidyl alcohols and their trityl ethers, but is also nucleophilic enough to displace primary bromides and secondary tosylates (Table 1). Usually, the opening of an epoxide, including the glycidyl derivatives described here, with a Grignard reagent requires Cu catalysis. 3, 4 Although the nucleophilic opening of epoxides with allylmagnesium chloride has been recognized, 5 there have been no reports on the addition of allylmagnesium chloride to glycidyl alcohols.