Eine einfache Synthese von (R.R)-3,4-Bis(diphenylphosphino)pyrrolidin (6a)und Rhodium Complexes for the Asymmetric Hydrogenation of a-(Acy1arnino)acrylic Acid DerivativesA simple synthesis of (R,R)-3,4-bis(diphenylphosphino)pyrrolidine (6a) and some N-substituted derivatives 6b-m is described. 61 and 6m are optically active tetraphosphanes, composed of two (R,R)-3,4-bis(diphenylphosphino)pyrrolidine units and a dicarboxylic residue. The structure of the parent compound 6a was determined by X-ray diffraction. From the phosphanes 6a -m the cationic 1,5-cyclooctadiene-bisphosphane-rhodium complexes 7a-rn were prepared. The complexes 71 and 7m are ligand bridged bis(rhodium) dications. The complexes 7a-m were used for the asymmetric catalytic hydrogenation of the a-(acy1amino)acrylic acid derivatives 9a -I. Enantiomeric excesses up to 100% were achieved. Between 1 and 70 at the optical yields do not depend on the hydrogen pressure. The substrateJcatalyst ratio can be as high as 5ooOoJ1. *) Zusammenarbeit bei der Verkiirzung der urspriinglich langeren Synthese von 6b.

Optical yields up to 100% are obtained in the heterogeneous hydrogenation of α-(acetylamino)cinnamic acid and its methyl ester in the presence of rhodium complexes of 3,4-(R,R)-bis(diphenylphosphino)pyrrolidine, bound covalently to silica.

Enantioselective Catalytic Hydrogenation of a-(Acetylamino)cinnamic Acid with a Rhodium Phosphane Complex in Aqueous SolutionThe synthesis of [(3R,4R)-3,4-bis(diphenylphosphino)-l,l-dimethylpyrrolidini~-P,~](l,5-cyc1ooctadiene)rhodium bis(tetrafluoroborate) (5) is described. With this water-soluble catalyst the sodium salt 6c of u-(Acetylamino)cinnamic acid (6a) is hydrogenated in aqueous solution to give (S)-N-acetylphenylalanine with 90% ee.

Aus 1‐Chlortricyclo[4.1.0.02,7]heptan (1) und den Lithium‐azirididen 4 wurden die 1‐(Tricyclohept‐1‐yl)aziridine 5a–d erhalten, die bei der Thermolyse zum Carbonitril 10 und (stereospezifisch) zum entsprechenden Olefin 11 fragmentierten. Als Mechanismus wird eine Retrocarbenspaltung der Bicyclobutan‐Einheit in 5 mit 13 als Zwischenstufe vorgeschlagen.

The parent title compound (VIIa) is prepared from (+)‐tartaric acid (I) with an overall yield of 45%; the structure of (VIIa) is determined by X‐ray diffraction (space group P21, Z=4).