Free radical ring expansion of fused cyclobutanones: a new ring expansion annulation stratagem
作者:Paul Dowd、Wei Zhang
DOI:10.1021/ja00026a037
日期:1991.12
Free-radical ring expansion of fused cyclobutanones: stereospecific construction of 5,7-, 6,7-, 7,7-, 8,7-, and 5,8-cis-fused bicyclic systems
作者:Paul Dowd、Wei Zhang
DOI:10.1021/jo00052a034
日期:1992.12
A new method of appending seven- and eight-membered rings to cycloalkenes is described. Treatment of selected alkene precursors with an omega-bromoalkyl ketene or a keteniminium salt leads to haloalkyl cyclobutanone formation. Tri-n-butyltin hydride promoted ring expansion then yields the annulated product. Since the initial cyclobutanone is cis fused, the final product is also produced stereospecifically with a cis ring fusion.
Free radical ring expansion of fused-methylenecyclobutanes
作者:Wei Zhang、Paul Dowd
DOI:10.1016/0040-4039(95)01830-b
日期:1995.11
Fused methylenecyclobutanes comprise a new free radical ring expansion system leading to cis-fused methylenecycloheptanes.