New General Method for Regio- and Stereoselective Allylic Substitution with Aryl and Alkenyl Coppers Derived from Grignard Reagents
作者:Yohei Kiyotsuka、Yuji Katayama、Hukum P. Acharya、Tomonori Hyodo、Yuichi Kobayashi
DOI:10.1021/jo802426g
日期:2009.3.6
Allylic substitution with sp2-carbon reagents (aryl and alkenyl anions) was realized by usingallylic picolinates and copper reagents derived from RMgBr and CuBr·Me2S to afford anti SN2′ products regio- and stereoselectively. Steric and electronic factors in the reagents and the size of the methylene substituents around the allylic moiety marginally affected the selectivity. The reaction system was
通过使用烯丙基吡啶甲酸酯和衍生自RMgBr和CuBr·Me 2 S的铜试剂实现Sp 2-碳试剂(芳基和烯基阴离子)的烯丙基取代,可以在区域和立体选择性地提供抗S N 2'产物。试剂中的立体和电子因素以及烯丙基部分周围的亚甲基取代基的大小在一定程度上影响了选择性。该反应系统也与烷基试剂相容。此外,该取代被应用于四元中心的构建和(-)-倍半茶烯酚的合成。吸电子的C的吡啶基的性质和螯合(═ ö)-C 5 H ^ 4 Ñ到MgBr 2 发现原位产生的碳负责替代的高效率。
New protocol for allylic substitution with aryl and alkenyl copper reagents derived from organolithiums
作者:Yohei Kiyotsuka、Yuichi Kobayashi
DOI:10.1016/j.tetlet.2008.10.002
日期:2008.12
Substitution of allylic picolinoates with copper reagentsderivedfrom sp2-carbon-lithiums and CuBr·Me2S was established to furnish anti SN2′ products with almost perfect regioselectivity and chirality transfer. The preparations of organolithiums such as lithium–halogen exchange and ortho lithiation were coupled to the substitution to install various sp2-carbon groups, which include Ph, 2,6-Me2C6H3
建立了由sp 2-碳锂和CuBr·Me 2 S衍生的铜试剂取代烯丙基吡啶啉酸酯,以提供具有几乎完美的区域选择性和手性转移的抗S N 2'产物。将有机锂的制备方法(例如锂-卤素交换和邻位锂化)与取代反应相结合,以安装各种sp 2-碳基团,其中包括Ph,2,6-Me 2 C 6 H 3,4 -Me-2,6- (MOMO)C 6 H 2,以及顺式和反式1-庚烯基。