Chiral aminoalcohol NOBIN for instantaneous chirality control of racemic but tropos BIPHEP–Rh(I)-complexes: highly enantioselective ene-type cyclization of 1,6-enynes catalyzed by the Rh(I)-complexes without use of acid

The tropos (chirally flexible) or atropos (chirally rigid) nature of BIPHEP–Rh complexes critically depends on amines and alcohols complexed. The BIPHEP–Rh complex with aminoalcohol NOBIN is significantly tropos and can be chirally controlled by aminoalcohol NOBIN instantaneously even at room temperature. The BIPHEP–Rh/NOBIN complex thus controlled can be used as an asymmetric catalyst to give higher enantioselectivity (up to 98% ee) and yield in ene-type cyclization of 1,6-enynes without use of acid.