Planar Chiral Phosphoramidites with a Paracyclophane Scaffold: Synthesis, Gold(I) Complexes, and Enantioselective Cycloisomerization of Dienynes.

Abstract

The key structural feature of the new phosphoramidites is a paracyclophane scaffold in which two aryl rings are tethered by both a 1,8-biphenylene unit and a O-P-O bridge. Suitable aryl substituents generate planar chirality. The corresponding gold(I) complexes promote the cycloisomerization of prochiral nitrogen-tethered dienynes. These reactions afford bicyclo[4.1.0]heptene derivatives displaying three contiguous stereogenic centers, with very high diastereoselectivity and up to 95 % ee.