A method for the transformation of cyclic ketones to homologous α,β-unsaturated ketones

Additions of dihalocarbenes to steroidal and related model olefins. Carbenic selectivity

“…SFurther splitting (~2 Hz) was observed in the triplet components. 6 Further splitting (~2 Hz) was observed. ' Further splitting (~3 Hz) was observed.…”

“…37 Under similar conditions, the use of adipic acid as the cata-lyst38 converted (70%) 9 to a mixture of 6 (87%) and 5 (13%), which provided 6 upon fractional distillation. The isomers could easily be differentiated by NMR; in CCI4, 6 had a vinyl resonance at 5.07 (broad singlet), whereas the vinyl resonance of 5 appeared as a multiplet centered at 5.23.37…”

“…16 Beyond this general concern, the medicinal potential of fluoro steroids has focused attention on the additions of fluorocarbenes to steroidal olefins. 43,6,19,20 With a few exceptions,21,22 most of this effort centered on CF2 additions to ring A and ring B double bonds. Usually the stereoselectivity (a or ß) of the difluorocyclopropanation was determined.20,23-28 Key reports included those of Knox et al, 27 and of Bond and Cornelia,29 which indicated that normal steroids with 5,6 unsaturation afforded /S-CF2 adducts.…”

Asymmetric Cyclopropanation and Epoxidation via a Catalytically Formed Chiral Auxiliary

“…The amino alcohol product was detected in the crude mixture, but upon basification, or any attempts of chromatographic separation (for full details see the Supporting Information, section D.6) of the salt 7 , degradation was observed. The products of the decomposition were identified as a mixture of geometrical isomers of enone 8 , presumably formed from a ring opening reaction of 7 [19a,b,h,i] . Interestingly, a thermal ring opening was observed by heating product 3 a in methanol, to give the same enone 8 as a single isomer in 70 % yield.…”

Organoquecksilber‐Verbindungen in der organischen Synthese

“…So konnte Stork[77] cyclische Ketone rnit Hilfe der Dichlorcarben-Ad- Wenn man sie mit einer in-situ-Reduktion rnit alkalischem NaBH4 koppelt, bietet diese Methode einen sehr bequemen Weg zur Herstellung stark verzweigter Eine Peroxymercurierung 1aRt sich auch rnit Quecksilber( 11)carboxylaten in Gegenwart von Wasserstoffperoxid und tert-Butylhydroperoxid durchfiuhren [GI.…”