Synthesis and reactivity of β-phenylselanyl α-oxoesters
摘要:
beta-Phenylselanyl alpha-oxoesters 2 were prepared by N-phenylselanyl morpholine treatment of alpha-oxoesters 1, oxidized into beta-unsaturated alpha-oxoesters 5 and subjected to the Wittig-Horner olefination. The diethyl (1-phenylselanylalkyl)maleates 6 have led, after [2,3]sigmatropic rearrangement of the corresponding selenoxides, to the diethyl 3-alkylidene-2-hydroxysuccinates 7. The 2-(t-butoxycarbonylamino)-3-alkylidenesuccinates 8 were prepared in a similar way. The decomposition of halo-adducts derived from compounds 6 has allowed the synthesis of the diethyl 3-alkylidene-2-halosuccinates 9 and 10. (C) 1997 Elsevier Science Ltd.
Synthesis and reactivity of β-phenylselanyl α-oxoesters
摘要:
beta-Phenylselanyl alpha-oxoesters 2 were prepared by N-phenylselanyl morpholine treatment of alpha-oxoesters 1, oxidized into beta-unsaturated alpha-oxoesters 5 and subjected to the Wittig-Horner olefination. The diethyl (1-phenylselanylalkyl)maleates 6 have led, after [2,3]sigmatropic rearrangement of the corresponding selenoxides, to the diethyl 3-alkylidene-2-hydroxysuccinates 7. The 2-(t-butoxycarbonylamino)-3-alkylidenesuccinates 8 were prepared in a similar way. The decomposition of halo-adducts derived from compounds 6 has allowed the synthesis of the diethyl 3-alkylidene-2-halosuccinates 9 and 10. (C) 1997 Elsevier Science Ltd.
Reduction of α-phenylselanyl imines derived from β-phenylselanyl α-oxoesters or PhSeCl assisted nucleophilic addition of primary amines to α,β-unsaturated esters have led to β-alkylamino phenylselenides 4, 5, 12 and 13 which were cyclised into aziridines 8, 9 and 14 after selenium activation. threo-Amino selenides led stereospecifically to cis-2,3-disubstituted aziridines. Depending on the structure
A synthesis of aziridine esters based on the cyclisation of amino selanyl esters induced by the selanyl group activation was developed with either the Meerwein salt or NBS. Twoasymmetricapproaches are proposed: the diastereoselective reductions of α-selanyl β-iminoesters derived from α-oxoesters, which lead to cis chiral aziridine esters 6 and 6′; and the diastereoselective conjugate additions of