Estelle Dumez

Tandem oxa-Michael addition–SN2′substitution of 4-chlorobut-2-yn-1-ol with nitroalkenes: a total allylic1,3-strain-controlled diastereoselective synthesis of3-vinylidenetetrahydrofurans

Bu t OK-promoted reaction of 4-chlorobut-2-yn-1-ol 1 with nitroalkenes 2 affords 3-vinylidenetetrahydrofurans 3 in good yields with total diastereoselectivity.

A synthetic route to allenylidene tetrahydrofurans

Radical mediated carbocyclization of bromoalkynyloxiranes 4 affords allenylidenetetrahydrofurans 5via a new α-hydroxyallene-terminated cyclization.

Studies towards a new one-pot heterocyclization: ButOK-promoted oxa- and aza-Michael addition–intramolecular carbocyclization of prop-2-ynyl alcohols and amines with α,β-disubstituted nitroalkenes

ButOK-promoted reaction of prop-2-ynyl alcohols 5 or N-methylprop-2-ynylamine 12 with nitroalkenes 1–4 affords 3-methylenetetrahydrofurans 6–9 and 3,4-dihydropyrans 10 and 11 or 3-methylenepyrrolidines 13–16, respectively, in moderate to good yields, with total allylic 1,3-strain-controlled diastereoselectivity.

Intramolecular cyclization of 1-nitroalkenyl radicals generated by one-electron oxidation of aci-nitro anions with CAN: stereoselective formation of 3,4-functionalized tetrahydrofurans

Upon one-electron oxidation by ammonium hexanitratocerate(IV) (CAN), aci-nitro anions 3a-d resulting from oxa-Michael addition of allylic alcohol to α,β-disubstituted nitroalkenes 1a-d undergo stereoselective radical cyclization into 3-nitro-4-nitrooxymethyltetrahydrofurans 6a-d and 3-nitro-4-hydroxymethyltetrahydrofurans 7,8a-d.

Synthesis and reactivity of α-allenylhydroxylamines: a new efficient access to 3,6-dihydro-1,2-oxazines

SmI2-promoted reduction of α-allenyl nitro derivatives 2a–f using controlled conditions provides either 3-amino-4-vinylidenetetrahydrofuran 3a or 3-hydroxylamino-4-vinylidenetetrahydrofurans 4b–f, which undergo intramolecular cyclization consistent with a reverse Cope elimination to afford 3,6-dihydro-1,2-oxazines 5b–f.

Stereocontrolled synthesis of anti-α-hydroxy-β-amino and anti-α, β-diamino acid derivatives by Epoxidation of 1-arylthio-1-nitroalkenes

Epoxidation of 1-tolylthio-1-nitroalkenes containing an allylic Boc-protected amino group yields cis-oxazolidinones 13, formed by intramolecular trapping of the presumed intermediate epoxides by the carbamate group. Epoxidation of the analogous Z- or Fmoc-protected derivatives yields the corresponding syn-epoxides which, although they cannot be isolated, can be trapped with aqueous ammonia, or more efficiently benzylamine, to give stereoisomerically pure anti-α,β-diamino acid derivatives.

The first [2,3]-sigmatropic rearrangement of allylic nitro compounds

Allylic nitro compounds 1a–d undergo [2,3]-sigmatropic rearrangement in refluxing 1,2,4-trichlorobenzene, to afford rearranged alcohols 3a–d and carbonyl compounds 4a–d; the heating, under the same conditions, of a mixture of nitroalkenes 7a–c, propargyl alcohols or amine 8 and ButOK promotes a one-pot formation of allylic alcohols 3a–c.