Diastereoselective hydroalkoxycarbonylation of terpenes and vinyl-estrone

Amidocarbonylation of alkenes at very low pressures with a Co2(CO)8/SbR3 system: two easy routes to reach N-acetyl-α-aminoacids

“…Finally, when the named air sensitive compound was used as a promoter in the amidocarbonylation of cyclohexene the results obtained were in agreement with those reported in entry (15).…”

“…All these prepared solutions were successfully used as catalytic media in the amidocarbonylation reaction and the good conversions were obtained using these solutions, very similar to those observed in entries (14,15,18). When o-tritolylstibine (o-TTS) was used as ligand, an air sensitive solid was isolated which was studied by FAB-mass spectrometry (positive mode) giving M + 1 an important fragment at m/z 546, this fragment is comparable with its theoretical isotopic distribution.…”

“…In spite of some isolated examples previously reported, amidocarbonylation reaction, in general, still unable to resolve the chirality induction in the obtained aminoacid [13][14][15][16]. In order to observe chiral induction in the aminoacid synthesis two new chiral stibine ligands (where R 1 , R 2 and R 3 are phenyl, thienyl, mesityl or phenyl, phenylethynyl, mesityl, respectively) were used with Co 2 (CO) 8 (entries 7,8,16,17).…”

Transition-Metal-Catalyzed Reactions in Steroid Synthesis

“…However, the ratio of the two epimers (approximately 80 / 20 ) could not be influenced by the use of either chiral or achiral phosphines. 49 …”

“…As the result of the hydroethoxycarbonylation of vinyl-estrone in the presence of Pd(II)-phosphine systems, the formation of the branched ester possessing a new stereogenic center was preferred. However, the ratio of the two epimers (approximately 80 / 20 ) could not be influenced by the use of either chiral or achiral phosphines …”