Rhodium-Catalyzed Double [2 + 2 + 2] Cycloaddition of 1,4-Bis(diphenylphosphinoyl)buta-1,3-diyne with Tethered Diynes: A Modular, Highly Versatile Single-Pot Synthesis of NU-BIPHEP Biaryl Diphosphines

Rhodium-catalyzed double [2 + 2 + 2] cycloaddition of 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne with tethered diynes provides a straightforward, single-pot procedure for the synthesis of a new class of tropos biaryl diphosphine, NU-BIPHEP. This methodology represents a significant improvement on existing multistep procedures. Enantiopure Lewis acid platinum complexes of these diphosphines are highly efficient catalysts for carbonyl-ene and Diels−Alder reactions, and ruthenium diphosphine-diamine complexes catalyze the asymmetric reduction of ketones to give ee's that rival those obtained with their BINAP counterpart.