Merck Patent Gesellschaft MIT Beschrankter Haftung

Hans U Reissig

Hans-Eckart Radunz

The invention relates to a process for the enantiomer-selective preparation of .gamma.-keto-.delta.-amino acid derivatives of the formula I ##STR1## characterized in that a compound of the formula II ##STR2## is converted, using a trialkylchlorosilane, into a compound of the formula III ##STR3## this compound is then reacted with a diazoacetate of the formula N.sub.2 CH.sub.2 COOR.sup.4 (R.sup.4 .noteq.H) to give a cyclopropane compound of the formula IV ##STR4## and then the compound IV is converted, by ring-opening and removal of the silyl groups, and where appropriate saponification, into the compound of the formula I, R.sup.1, R.sup.2, R.sup.3, R.sup.4 and R.sup.5 having the meanings indicated in claim 1.

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Darmstadt, Germany

Hans U Reissig