Catalytic Enantioselective 1,2-Diboration of 1,3-Dienes: Versatile Reagents for Stereoselective Allylation
作者:Laura T. Kliman、Scott N. Mlynarski、Grace E. Ferris、James P. Morken
DOI:10.1002/anie.201105716
日期:2012.1.9
More with boron: The development of catalyticenantioselective 1,2‐diboration of 1,3‐dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1‐disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized
Picolinoxy Group, a New Leaving Group for anti S<sub>N</sub>2′ Selective Allylic Substitution with Aryl Anions Based on Grignard Reagents
作者:Yohei Kiyotsuka、Hukum P. Acharya、Yuji Katayama、Tomonori Hyodo、Yuichi Kobayashi
DOI:10.1021/ol800300x
日期:2008.5.1
The picolinoxy group was found to be an extremely powerful leavinggroup for allylic substitution with aryl nucleophiles derived from ArMgBr and CuBr*Me2S. The substitution proceeds with anti SN2' pathway and with high chirality transfer. The electron-withdrawing effect of the pyridyl group and chelation to MgBr2 are likely the origin of success. Results suggesting these effects were obtained.