[3,3]-Rearrangements of Phosphonium Ylides

Abstract

Allylic phosphonium ylides are readily generated by the combination of an allylic alcohol, a carbene, and a chlorophosphite. Here we demonstrate that these intermediates undergo a thermal [3,3]-rearrangement to provide single isomers of homoallylic phosphonates in good to excellent yields. This new reaction manifold for phosphorus ylides is tolerant of a range of substitution patterns on the reactants and provides access to structurally complex intermediates for the synthesis of enzyme inhibitors, aminophosphonic acids, and natural products.

Contemporaneous Dual Catalysis: Chemoselective Cross-Coupling of Catalytic Vanadium–Allenoate and π-Allylpalladium Intermediates

“…Finally, the previously unreactive substrate bearing a single alkyl substituent reacted successfully, and the corresponding product was isolated in extremely high yield (91%) (entry 8). The product in entry 6 is a known compound, and its stereochemistry was assigned according to literature data . The double bond geometries of products in entries 7 and 8 were then given by analogy with this compound.…”

Sigmatropic rearrangements of ‘onium’ ylids

“…5.3 [3,3]-Rearrangements [3,3]-Sigmatropic rearrangements of onium ylids are rare; a recent report has described the first such reactions of phosphonium ylids (Scheme 48), thus allowing synthesis of 2-allyl-2-phosphonoesters from allyldiethylphosphites. 53…”

Molecular Rearrangements: Part 1. Pericyclic Reactions

“…Product distributions observed with electron-rich ortho-substituents have been attributed to competing chair-and boat-like transition states for the initial [ (25) have been shown to undergo nitrosation adjacent to the carbonyl group followed by [3,3]-sigmatropic rearrangement to give oxazine products (26). 23 Stereodefined monoprotected allylic 1,2-diol (27) and its diastereomer have been de converted into stereodefined propenylimidazolidinone (30) and its diastereomer by successive diastereoselective [3,3]-sigmatropic rearrangements of the initially formed allylic cyanates (28), (29), or their diastereomers as shown. 24 The stereoselectivity of the MOM ether-directed, transition metal-catalysed azaClaisen rearrangement of O-(4-methoxymethoxypent-2-en-1-yl) trichloroacetimidate to N -(4-methoxymethoxypent-1-en-3-yl) trichloroacetimidate has been studied under various conditions.…”