Stereoselective sonochemical reductive silylation of geminal dibromocyclopropanes by bulk magnesium
作者:Jonathan Touster、Albert J. Fry
DOI:10.1016/s0040-4039(97)01453-6
日期:1997.9
trimethysilyl chloride and a bicyclic 1,1-dibromocyclopropane in the presence of bulk magnesium affords 1-trimethylsilyl-1-bromocyclopropanes in 72–93% yield. The sonochemical reactions proceed stereoselectively to afford as the major product the product in which the trimethylsilyl group is cis to the hydrogen atoms at the ring juncture.
On the stereoselectivity of iodocarbene and -carbenoid additions to cyclic alkenes
作者:Eckehard V. Dehmlow、Jörg Stütten
DOI:10.1016/0040-4039(91)80764-w
日期:1991.10
Exclusive formation of endo adducts 3d-f, 9, 10, 11 is observed in both carbene and carbenoid CHI additions with eight to twelve membered-ring alkenes. Cyclopentene, in contrast, gives exo compound 4a as only isolable product, whereas cyclohexene and cycloheptene yield both types of product. :CHBr (from HCBr3 and NaN(SiMe3)2) exhibits similar although less pronounced trends: only cyclodecene and cyclododecene lead to pure endo adducts 7e,f.