Catalytic asymmetric arylative cyclization of alkynals: phosphine-free rhodium/diene complexes as efficient catalysts

The study describes that the addition/cyclization of arylboronic acids to alkynals proceeds smoothly by the use of a rhodium/ diene catalyst, leading to cyclic allylic alcohols with a tetrasubstituted olefin and effective asymmetric catalysis is achieved by the use of chiral diene ligands. A range of arylboronic acids is efficiently coupled by employing a chiral bicyclo-[2.2.2]octadiene ligands with these substrates in very good enantiomeric excess.