受铑催化羧酸经济向丙二烯中添加羧酸的机理研究的启发,已开发出铑催化的不同亲核试剂与消旋烯丙基碳酸酯的动态动力学不对称烯丙基化反应。在中性条件下可以获得很高的区域选择性和对映选择性,此外,化学选择性可以通过不同的二膦配体来控制。(R,R)-QuinoxP *导致酚的选择性O-烯丙基化,而当嵌入(S,S)-DIOP作为配体时,2-萘酚首次以高对映选择性被邻-C-烯丙基化。为此,羟基吡啶可以通过Rh I /(S)-DTBM-Segphos的中间体与先前报道的对丙二烯的原子经济加成反应相同。
Enantioselective Palladium(II)-Catalyzed Formal [3,3]-Sigmatropic Rearrangement of 2-Allyloxypyridines and Related Heterocycles
作者:Alessandro Rodrigues、Ernest E. Lee、Robert A. Batey
DOI:10.1021/ol9025759
日期:2010.1.15
Enantioselectivepalladium(II)-catalyzed formal [3,3]-sigmatropic rearrangement of (E)- and (Z)-allyloxy substituted N-heterocycles generates N-allyl N-heterocyclic amides in good yields and high enantioselectivities (up to 96% ee). The chiral palladacycle COP-Cl (5 mol %) is used as a catalyst with silver(I) trifluoroacetate (10 mol %) at 35−45 °C. Examples of heterocycles synthesized include 2-pyridones