Cyclization of α,β,ψ,ω-Unsaturated Bisphosphonates Using Organolithium-Initiated Conjugate Addition−Michael Tandem Reaction

The reaction of α,β,ψ,ω-unsaturated bisphosphonates 1 with organolithiums afforded conjugate addition−Michael tandem cyclization products 3 and deprotonation−Michael cyclization products 5 . Highly stereoselective deuteration of the intermediates proved the stereochemistry of lithium phosphonates 10, 13, and 15 .