Structure and Reactivity of Phosphonate Anions

Of course, the main interest in the Homer-Wadsworth-Emmons reaction is its application in synthesis. New biologically active molecules synthesised include endothelin receptor antagonist S-0139, which requires phosphonate 

A new strategy for accessing cylohexenes and related ring structures devised by Chollerton et al. involves an intramolecular radical addition to an unactivated olefin in conjunction with an intramolecular Horner-Wadsworth- 

Reagents (i) lauroyl peroxide (0.1-0.2 equiv.),1,2-dichloroethane, reflux (ii) BusSnH (AIBN), PhMe, reflux (iii) K2CO3/18-crown-6, PhMe, reflux (iv) NaH, THF 

the aldehyde is treated with two phosphonates (134), one ( )-selective and one (Z)-selective, that contain the exact same auxiliary. This approach relies on the observation that (E)- or (Z)-selective phosphonates generally react with opposite enantiotopic group preference affording one ( )- and one (Z)-product with opposite absolute configuration at the allylic stereocentre. Both PKR routes described offer the potential to increase material throughput and selectivity compared with conventional kinetic resolution, which will surely lead to further reports on this topic in the future. 

Phosphorus, Sulfur, Silicon Relat. Elem., 1998,143, 221. 

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