Controllable Highly Stereoselective Reaction of in situ Generated Magnesium Dienolate Intermediates with Different Electrophiles
摘要:
In this paper, we have described an efficient controllable stereoselective a-acylation and -allylation reaction of the magnesium dienolate intermediates generated in situ from the Fe(III)-catalyzed reaction between 2,3-allenoates and Grignard reagents with different electrophiles to afford 2-acylated or allylated 3(Z)- or (E)-alkenoates depending on the nature of the electrophiles and reaction conditions. The distinct stereoselectivity may be caused by the isomerization of metallic Z-1,3-dienoate to E-1,3-dienoate via the intermediacy of anti-allylic MgCl and syn-metallic species.