SYNTHETIC STUDIES ON QUINOCARCIN AND ITS RELATED-COMPOUNDS .2. SYNTHESIS OF AN ENANTIOMERIC PAIR OF THE ABC RING-SYSTEM OF QUINOCARCIN

An enantiomeric pair of the ABC ring system (5 and ent-5) of quinocarcin (1), a patent antitumor antibiotic, was synthesized in >95% ee with an. aim to disclose novel aspects of the structure-activity relationships of 1. The key features of the synthesis consist of novel diastereoselective reduction of 1,3-disubstituted isoquinoline derivatives 29 and ent-29 to control stereochemistries at the C6 and C11a positions in 5 and ent-5 simultaneously in a single step and intramolecular N,O-acetal formation of amino aldehydes 6 and ent-6 to complete the requisite skeletal framework.