Facile Conversion of Cyclopropanols into Linear Conjugate Enones
作者:Wei-Bo Han、Shao-Gang Li、Xiao-Wei Lu、Yikang Wu
DOI:10.1002/ejoc.201402175
日期:2014.6
A practical method for the conversion of 1,2-disubstituted cyclopropanols derived from Kulinkovich cyclopropanation into linearenones was developed. The approach features regioselective cleavage of the cyclopropane rings in EtOH at ambient temperature with inexpensive and readily available Co(acac)2 as the catalyst and air as the reagent. The crude intermediate peroxides were directly reduced with
作者:Danielle L. Aubele、Christopher A. Lee、Paul E. Floreancig
DOI:10.1021/ol0359259
日期:2003.11.1
are employed as oxocarbenium ion progenitors and allylsilanes are used as nucleophiles. Cyclizations proceed efficiently inside Lewis acidic micelles in water, demonstrating that colloidal suspensions can protect highly electrophilic intermediates from hydrolysis. Reactions are experimentally facile and useful in the preparation of a variety of vinyl- and aryl-substituted tetrahydropyrans with excellent
作者:Marie E. Krafft、Carmelinda A. Juliano、Ian L. Scott、Colin Wright、Michael D. McEachin
DOI:10.1021/ja00005a038
日期:1991.2
The regioselectivity of the cobalt-mediated cocyclization of an alkene, an alkyne, and carbon monoxide has been shown to be directed by the use of a soft atom, either sulfur or nitrogen, tethered to the alkene partner by a carbon chain. Direction from the homoallylic position is more efficient thant from the allylic or bishomoallylic position. A rationale is proposed to explain this observation. Studies
Steric control in the pauson cycloaddition: Further support for the proposed mechanism
作者:Marie E. Krafft
DOI:10.1016/0040-4039(88)85318-8
日期:1988.1
Dicobalthexacarbonyl complexes of internal alkynes react with olefins to give cyclopentenones with a high degree of regiocontrol. Analogous reactions of terminal alkynes give rise to regioisomeric mixtures of cyclopentenones.
migratory ether formation strategy. In contrast to the common pathway of direct opening of epoxides, Me3Al was found to promote an unprecedented ether addition reaction, opening a neighboring epoxide. The resulting oxonium intermediate triggers a 1,3‐methyl shift to yield 2‐deoxyribital products. When the hemiacetal auxiliary is a monosaccharide, the sugar ring is expanded by four atoms to give the corresponding