Regio- and stereocontrolled alkylative ring opening of unsymmetrical 8-oxabicyclo[3.2.1]octene systems. Synthesis of highly substituted hydroxycycloheptenyl sulfones.
作者:Odón Arjona、Alfonso de Dios、Joaquín Plumet
DOI:10.1016/s0040-4039(00)60150-8
日期:1993.11
organolithium mediated bridge opening of unsymmetrically substituted 8-oxabicyclo[3.2.1]octenederivatives 6, 7, proceeds with complete regio- and stereoselectivity to afford highly functionalized hydroxycycloheptenyl sulfones 10, 12 in high yields. It was also found possible to control the conjugate addition/β-elimination sequence towards the synthesis of adducts 8, 9, 11.
The present application relates to thiazolylidene containing compounds of formula (I)
wherein R1, R2, R3, and R4 are as defined in the specification. The present application also relates to compositions comprising such compounds, and methods of treating conditions and disorders using such compounds and compositions.
Highly stereoselective, total synthesis of β-c-hexopyranosyl derivatives
作者:Daniela Fattori、Pierre Vogel
DOI:10.1016/s0040-4039(00)77480-6
日期:1993.2
One Diels-Alder adduct of furan to 1-cyanovinyl acetate is converted to 8-oxabicyclo[3.2.1]oct-6-en-2-one which is transformed into β-C-hexopyranosides including 2-deoxy and 2,3-unsaturated derivatives.
Sulfone Directed Alkylative Bridge Cleavage of Oxabicyclic Vinyl Sulfones with Organolithium Reagents
作者:Odon Arjona、Alfonso de Dios、Roberto Fernandez de la Pradilla、Joaquin Plumet、Alma Viso
DOI:10.1021/jo00093a024
日期:1994.7
An efficient regio- and stereocontrolled methodology for the alkylative bridge cleavage of oxabicyclic vinyl sulfones is described. A range of 7-oxabicyclo[2.2.1]heptenyl and 8-oxabicyclo[3.2.1]octenyl sulfones has been found to undergo an overall syn S(N)2' opening when treated with a wide variety of organolithium reagents and lithium aluminum hydride. In this manner, highly functionalized cyclohexenyl and cycloheptenyl sulfones, versatile synthetic intermediates, are now available in high yields. The complete stereoselectivity encountered in the exo conjugate addition may be explained by chelation of the organometallic reagent with the oxygen bridge and steric factors. Furthermore, less-strained substrates allow for complete control of the addition and elimination stages.