Synthesis of 1,1-Dibromo-3-hydroxyalkanes via Opening of Cyclic Sulfates
作者:Hans Christian Stiasny
DOI:10.1055/s-1996-4193
日期:1996.2
3-Alkoxy-1,1-dibromoalkanes are interesting substrates for diastereoselective bromine/lithium exchange reactions. A general route to the precursor 1,1-dibromo-3-hydroxyalkanes is described here via reaction of dibromomethyllithium with cyclic sulfates of 1,2-diols.
Cycloaddition reactions of silyloxyacetylenes with ketenes: synthesis of cyclobutenones, resorcinols, and .DELTA.-6-tetrahydrocannabinol
作者:Conrad J. Kowalski、G. Sankar. Lal
DOI:10.1021/ja00219a073
日期:1988.5
La cycloaddition du cetene avec des composes acetyleniques donne des cyclobutene-2ones. Ces dernieres reagissent avec des composes acetyleniques pour donner des resorcinols et le tetrahydro-6a,7,10,10a cannabinol
La cycloaddition du cetene avec des composes acetyleniques donne des cyclobutene-2ones。Ces dernieres reagissent avec des composes acetyleniques pour donner des resorcinols et le tetrahydro-6a,7,10,10a 大麻
Ester homologation via .alpha.-bromo .alpha.-keto dianion rearrangement
作者:Conrad J. Kowalski、M. Serajul Haque、Kevin W. Fields
DOI:10.1021/ja00291a063
日期:1985.3
Homologation des esters RCO 2 Et (dans lesquels le groupe R est primaire, secondaire, tertiaire, aryl, alcenyl, alcynyl) et de quelques lactones par traitement avec le dibromomethyllithium
Homologation desesters RCO 2 Et (dans lesquels le groupe Rest primaire, secondaire, tertiaire, aryl, alcenyl, alcynyl) et de quelques lactones par traitement avec le dibromomethyllithium
A convenient preparation of mono- or gem-di-halogenoalkenes from α-sulfonyl carbanions and halogenolithiocarbenoïds
Various α-sulfonylcarbanions have been shown to react at low temperature with di- or tri-halogenolithiocarbenoïds, to give 1-mono- or 1,1-di-halogenoalkenes. Bromocarbenoïds gave better results than their chloro-analogues. Reaction of di-bromolithiomethane with α-lithiated sulfones gives a high yield of vinylic bromides, the stereochemistry of which is cleanly E. Evidence is presented that the carbenoïd
A directed chiral synthesis of amino acids from boronic esters
作者:Donald S. Matteson、Ellen C. Beedle
DOI:10.1016/s0040-4039(00)96547-x
日期:1987.1
Conversion of (s)-pinanediol (1S)-1-haloalkylboronates to (1R)-1-azido boronates, homologation with (dichloromethyl)lithium to 1-chloro-2-azido boronates, oxidation with sodium chlorite to the α-azido acids, and catalytic hydrogenation yielded L-amino acids, 92-96% enantiomeric excess.