ADVANCED SYNTHESIS & CATALYSIS;
JAN 17 2018.
Citações Web of Science:
This work discloses the first examples of an effective enantioselective oxy-Heck-Matsuda reaction using a variety of styrenic olefins to generate chiral dihydrobenzofurans. The reaction proceeds in moderate to good yields, with high trans diastereoselectivity (up to 20:1) in enantioselectivities up to 90:10 using the N,N-ligand pyrimidine-bisoxazoline (PyriBox). The oxy-Heck-Matsuda reactions were carried out under mild conditions and rather low catalyst loadings. The feasibility and practicality of the process is demonstrated by a concise total synthesis of the neolignan (-)-conocarpan. X-ray diffraction of an advanced brominated intermediate in the route to (-)-conocarpan has allowed the unequivocal assignment of the absolute stereochemistry of the oxy-Heck-Matsuda aryldihydrobenzofuran products. A rationale for the mechanism operating in these enantioselective oxy-Heck-Matsuda reactions is also presented. (AU)