Cyclic Phosphine Oxides and Phosphinamides from Di-Grignard Reagents and Phosphonic Dichlorides: Modular Access to Annulated Phospholanes. 
The reaction between 1,4-di-Grignard reagents and phosphonous(III) dichlorides is a classical method for the direct synthesis of phospholanes.  Reported here is an extension of this approach to the preparation of value-added, annulated phospholane oxides, achieved through the combination of carbocyclic-fused di-Grignard reagents and readily available phosphonic(V) dichlorides.  The procedure is amenable to (benz)annulation at both the 2,3- and 3,4-positions of the phospholane ring, and a variety of aliphatic, cyclic and aryl P-electrophiles are tolerated in reasonable to excellent yields.