Enantioselective iridium-catalyzed carbonyl allylation from the alcohol or aldehyde oxidation level using allyl acetate as an allyl metal surrogate
Enantioselective iridium-catalyzed carbonyl allylation from the alcohol or aldehyde oxidation level using allyl acetate as an allyl metal surrogate
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DOI：
10.1021/ja802001b
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发表时间：
2008-05-21
影响因子：
15
通讯作者：
Krische, Michael J.
中科院分区：
文献类型：
--
作者：
Kim, In Su;Ngai, Ming-Yu;Krische, Michael J.
基于转移氢化C-C偶联，描述了从醇或醛的氧化水平进行高对映选择性的羰基烯丙基化的方案。在[IrCl(CoD)](2)和(R)-BINAP衍生的铱催化剂存在下，与苄基醇1a-i反应可得到C-烯丙化2a-i产物。以异丙醇为末端还原剂，在由[IrCl(CoD)](2)和(-)-TMBTP衍生的Ir催化剂存在下，乙酸烯丙酯与芳醛3a-i反应生成相同的C-烯丙化2a-i产物。在所有被检查的情况下，观察到对映体选择性的例外水平。因此，在没有任何预制的烯丙基金属试剂的情况下，从醇或醛的氧化水平实现了对映体选择性的羰基烯丙基化。这些研究定义了超出氧化水平边界的羰基加成反应与预制的有机金属试剂的背离。
Protocols for highly enantioselective carbonyl allylation from the alcohol or aldehyde oxidation level are described based upon transfer hydrogenative C-C coupling. Exposure o benzylic alcohols 1a-i in the presence of an iridium catalyst derived from [IrCl(cod)](2) and (R)-BINAP delivers products of C-allylation 2a -i. Employing isopropanol as terminal reductant, exposure of allyl acetate to aryl aldehydes 3a-i in the presence of an iridium catalyst derived from [IrCl(cod)](2) and (-)-TMBTP delivers identical products of C-allylation 2a-i. In all cases examined, exception levels of enantioselectivity are observed. Thus, enantioselective carbonyl allylation is achieved from the alcohol or aldehyde oxidation level in the absence of any preformed allylmetal reagents. These studies define a departure from preformed organometallic reagents in carbonyl additions that transcend the boundaries of oxidation level.