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.
Diastereoselective bromine/lithium-exchange applied to the synthesis of a C-1/C-9-segment of the bryostatins
作者:Reinhard W Hoffmann、Hans Christian Stiasny
DOI:10.1016/0040-4039(95)00821-s
日期:1995.6
The α-bromo-alkyllithium compounds 5 are generated by diastereoselective bromine/lithium exchange on the dibromo-compound 4. The minor carbenoid 5b generated cyclizes spontaneously at −110°C to the bicyclo[3.1.0]hexane 6, thus, leaving the major carbenoid 5a in diastereomerically pure form. Application of the boronate extension reaction to this carbenoid 5a ed to 1,3- or 1,6-diol derivatives, viz.