Chiral Phosphoric Acid-Governed Anti-Diastereoselective and Enantioselective Hetero-Diels−Alder Reaction of Glyoxylate
摘要:
A highly enantioselective anti-diastereoselective hetero-Diets-Alder reaction between a glyoxylate and siloxy- or methoxydienes using a chiral phosphoric acid catalyst that possesses less bulky phenyl groups at the 3 and 3' positions of binaphthyl has been developed. The diastereoselectivities presented are disparate to those previously reported for hetero-Diets-Alder reactions catalyzed by a chiral Lewis acid.
A new protocol has been developed for the borylation of conjugated alkenyl methyl ethers using B2Pin2 via C–O bond cleavage catalyzed by Ni(II). In this cross-coupling reaction, both E/Z isomers of alkenyl ethers are converted into (E)-alkenyl boronic esters with good reactivity. This transformation exhibits high chemoselectivity in the presence of competitive C–O bonds such as aryl ether, ester, amide