Regioselective and Stereospecific Cross-Coupling of Primary Allylic Amines with Boronic Acids and Boronates through Palladium-Catalyzed C?N Bond Cleavage
Regioselective and Stereospecific Cross-Coupling of Primary Allylic Amines with Boronic Acids and Boronates through Palladium-Catalyzed C?N Bond Cleavage
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DOI：
10.1002/anie.201109171
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发表时间：
2012-01-01
影响因子：
16.6
通讯作者：
Tian, Shi-Kai
中科院分区：
文献类型：
--
作者：
Li, Man-Bo;Wang, Yong;Tian, Shi-Kai
烯丙基亲电试剂与硼酸和硼酸盐的交叉偶联对于C13C键的形成和将烯丙基部分引入目标化合物是非常有用的。[1，2]烯丙基卤化物、[3]酯、[4]碳酸酯、[4f，g，5]磷酸酯、[6]和醇[7]已被鉴定为具有显著不同的反应性和选择性的烯丙基亲电试剂。值得注意的是，使用烯丙醇作为烯丙基亲电试剂在原子经济性方面非常有吸引力，因为离去的OH基团具有17 amu的质量，其远小于卤素或OR（R26H）基团的质量。然而，据报道，非手性烯丙醇与硼酸的偶联得到外消旋产物。[7f]据我们所知，质量小于17 amu的离去基团还没有报道用于烯丙基亲电试剂与有机硼的偶联反应，与烯丙基卤化物和醇衍生物相比，烯丙基胺很少被用于在交叉偶联反应中将烯丙基部分传递到最终产物，这是由于氨基的离去能力差。[8]在1995年，Trost埃塔尔.描述了末端叔烯丙基胺与硼酸的镍催化的交叉偶联。[8g]虽然该反应的底物范围窄，选择性差，但这项研究以及我们对C3N键断裂的兴趣[9]促使我们研究使用伯烯丙基胺作为烯丙基亲电试剂的可能性。在此，我们报道了具有16 amu质量的NH 2基团在钯催化的伯烯丙基胺与硼酸的区域选择性和立体特异性交联中作为有效的离去基团，
The cross-coupling of allylic electrophiles with boronic acids and boronates is extremely useful for the formation of CÀC bonds and for the introduction of the allyl moieties to target compounds.[1, 2] Allylic halides,[3] esters,[4] carbonates,[4f, g, 5] phosphates,[6] and alcohols [7] have been identified as allylic electrophiles with significantly different reactivity and selectivity. It is noteworthy that the employment of an allylic alcohol as the allylic electrophile is very attractive with respect to atom economy because the leaving OH group has a mass of 17 amu, which is much smaller than that of a halo or an OR (R ¼6 H) group. Nevertheless, the coupling of an achiral allylic alcohol with a boronic acid has been reported to afford a racemic product.[7f] To our knowledge, a leaving group with a mass smaller than 17 amu has not yet been reported for the coupling of an allylic electrophile with an organoboron.In contrast to allylic halides and alcohol derivatives, allylic amines have rarely been employed to deliver allyl moieties to final products in the cross-coupling reactions owing to the poor leaving ability of the amino group.[8] Notably, in 1995 Trost etal. described a nickel-catalyzed cross-coupling of terminal tertiary allylic amines with boronic acids.[8g] Although the reaction suffers from narrow substrate scope and poor selectivity, this study, together with our interest in CÀN bond cleavage,[9] prompted us to investigate the possibility of using primary allylic amines as the allylic electrophiles. Herein, we report that the NH2 group, having a mass of 16 amu, acts as an effective leaving group in the palladium-catalyzed regioselective and stereospecific crosscoupling of primary allylic amines with boronic acids and