Marie-George Guillerez

New allyl group acceptors for palladium catalyzed removal of allylic protections and transacylation of allyl carbamates

Abstract Allyl carboxylates, carbamates and phenoxides may be cleaved or transacylated in the presence of palladium catalyst and either phenyltrihydrosilane or N-methyl-N-(trimethylsilyl)-trifluoroacetamide. These reactions are totally compatible with the presence of Boc and, as far as phenyltrihydrosilane is concerned, Fmoc protections.

Regio- and stereoselective reductive opening of diene-ester derived monoepoxides with palladium catalyst and dimethylamine–borane complex

Abstract Monoepoxides of diene-esters are regio- and stereoselectively reduced to homoallylic alcohols by dimethylamine–borane complex in the presence of acetic acid and catalytic amounts of Pd(PPh 3 ) 4 .

Cyclopropane ring formation by an SmI2 mediated cyclisation of δ-halo-α,β-unsaturated esters

Abstract δ-Iodo- and δ-bromo-α,β-unsaturated esters with various substituents at the β- and γ-positions readily cyclise to cyclopropane compounds in the presence of samarium diiodide and a proton source.

Diastereoselective SmI2-Mediated 3-exo-trig Cyclisation of δ-Oxo-Alkylidenemalonates to Cyclopropanols

In the presence of samarium diiodide and a proton donor (tert-butanol or phenol), δ-oxo-y.y-disubstituted-alkylidenemalonates readily cyclise according to the 3-exo-trig mode to give. depending on the exact nature of the substrate, trans and cis cyclopropanols or lactones derived from the cis isomers. Total stereoselectivity towards the formation of trans cyclopropanols is observed with di-tert-butyl alkylidenemalonates when PhOH is used as the protonating agent.