Synthesis of Epoxides from Alkyl Bromides and Alcohols with in Situ Generation of Dimethyl Sulfonium Ylide in DMSO Oxidations
Direct conversion of the readily available alkyl bromides and alcohols to value-added epoxides using dimethyl sulfoxide (DMSO) under mild reaction conditions has been developed. Benzyl and allyl bromides, and activated and unactivated alcohols all proceeded smoothly to give epoxides in high to excellent yield. Dimethyl sulfide, generated by DMSO oxidations, was in situ elaborated to form the substituted dimethyl sulfonium ylide species that participates in the Corey-Chaykovsky epoxidation in a domino and one-pot fashion, respectively.
A facile tetrahydrothiophene-catalyzed ylide route to vinyloxiranes
Access to vinyloxiranes using aldehydes and allylic bromides in the presence of 1-5 mol% tetrahydrothiophene is reported. Both aliphatic and aromatic aldehydes work well in this reaction and the catalyst loading could be reduced as low as 0.5 mol%.
Li, Kai,Deng, Xian-Ming,Tang, Yong
p. 2074 - 2075
(2007/10/03)
Simple synthetic method of allyl- and vinyl-epoxides by allylation of carbonyl groups with allylic tins catalyzed by PbI2-HMPA
Allyl epoxides were prepared by the chemoseletive allylation at the carbonyl groups of a-bromo ketones with allylic tin, where PbI2-HMPA effected as a chemoselective catalyst. Moreover, vinyl epoxides were obtained in one pot procedure by the P
Shibata, Ikuya,Fukuoka, Shoji,Baba, Akio
p. 533 - 534
(2007/10/03)
Chloroallyl Anion: Highly Regio- and Diastereoselective α-Addition of Chloroallyl Zinc Reagent to Carbonyl Compounds
The chloroallyl zinc reagent generated insitu by deprotonation of allyl chloride in the presence of lithium diisopropylamide and zinc chloride undergoes highly regio- and diastereoselective α-addition to carbonyl compounds to give syn chlorohydrins which
Mallaiah, K.,Satyanarayana, J.,Ila, H.,Junjappa, H.
p. 3145 - 3148
(2007/10/02)
A FIRST EXAMPLE OF CATALYTIC YLIDE EPOXIDATION REACTION: FACILE SYNTHESIS OF VINYL EPOXIDES FROM ALDEHYDES CATALYZED BY DIISOBUTYL TELLURIDE
In the presence of cesium carbonate, a variety of aldehydes can be epoxidized directly with allyl bromide at 50 deg C under solid-liquid phase transfer condition by use of a catalytic amount of diisobutyl telluride to afford vinyl epoxides in good yields
Zhou, Zhang-Lin,Shi, Li-Lan,Huang, Yao-Zeng
p. 7657 - 7660
(2007/10/02)
A Facile Synthesis of α,β-Unsaturated Epoxides via Allyldi-isobutyltelluronium Bromide
In the presence of solid KOH, allyldi-isobutyltelluronium bromide 2 reacts directly with aromatic aldehydes at room temperature under solid-liquid phase-transfer conditions to afford α,β-unsaturated epoxides 3 in excellent yields.
ACTION DU CHLOROALLYLLITHIUM SUR LES ALDEHYDES ET LES CETONES: SYNTHESE EN UNE ETAPE D'ALCOOLS β-ETHYLENIQUES γ-CHLORES DE CONFIGURATION Z ET D'EPOXYDES α-ETHYLENIQUES BI- OU TRI-SUBSTITUES
Chloroallyllithium readily reacts with aliphatic and aromatic aldehydes and ketones to produce, in a one-step reaction, Z-γ-chlorinated-β-ethylenic alcohols and bi- or tri-substituted epoxides.
Doucoure, A.,Mauze, B.,Miginiac, L.
p. 139 - 148
(2007/10/02)
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