Rhodium-catalyzed asymmetric synthesis of 1,1-disubstituted 1,3-dihydrobenzo[c]furans from prochiral triynes and internal alkynes

The cationic rhodium/Binap system was found to be an efficient catalytic system for the [2 + 2 + 2] cycloaddition of prochiral triynes with internal alkynes. The optimization of the catalytic system allowed the construction of 1,1-disubstituted 1,3-dihydrobenzo[c]furans containing a quaternary carbon stereogenic centers in fair yields and moderate enantiomeric excesses.