Intermediates of peripherally selective N-carbonyl-3,4,4-trisubstituted piperidine opioid antagonists

An intermediate which is a trans-3,4-stereoisomer of the compound of the formula ##STR14## wherein R.sup.1 is hydrogen or (C.sub.1 -C.sub.5)alkyl;

• R.sup.2 is hydrogen, (C.sub.1 -C.sub.5)alkyl, or (C.sub.2 -C.sub.6)alkenyl;
• R.sup.3 is hydrogen, (C.sub.1 -C.sub.10)alkyl, (C.sub.3 -C.sub.10)alkenyl, (C.sub.3 -C.sub.8)cycloalkyl, (C.sub.3 -C.sub.8) cycloalkyl-(C.sub.1 -C.sub.3) alkyl, phenyl, (C.sub.5 -C.sub.8) cycloalkenyl, (C.sub.5 -C.sub.8)cycloalkenyl-(C.sub.1 -C.sub.3)alkyl, or phenyl-(C.sub.1 -C.sub.3) alkyl;
• R.sup.4 is hydrogen, (C.sub.3 -C.sub.8) cycloalkyl, (C.sub.1 -C.sub.10) alkyl, (C.sub.3 -C.sub.10)alkenyl, (C.sub.3 -C.sub.8)cycloalkyl-(C.sub.1 -C.sub.3)alkyl, phenyl or phenyl-(C.sub.1 -C.sub.3) alkyl;
• Z is an amino blocking group when R.sup.4 is not phenyl or Z is hydrogen when R.sup.4 is phenyl;
• and
• n is 1-3.