Cascade radical reaction of substrates with a carbon-carbon triple bond as a radical acceptor.

The limitation of hydroxamate ester as a chiral Lewis acid coordination moiety was first shown in an intermolecular reaction involving a radical addition and sequential allylation processes. Next, the effect of hydroxamate ester was studied in the cascade addition-cyclization-trapping reaction of substrates with a carbon-carbon triple bond as a radical acceptor. When substrates with a methacryloyl moiety and a carbon-carbon triple bond as two polarity-different radical acceptors were employed, the cascade reaction proceeded effectively. A high level of enantioselectivity was also obtained by a proper combination of chiral Lewis acid and these substrates.