SYNTHETIC STUDIES ON NOGALAMYCIN CONGENERS ; TOTAL SYNTHESES OF (+)-NOGARENE, (+)-7-DEOXYNOGAROL, AND (+)-7-CON-O-METHYLNOGAROL

Article abstract of DOI:10.1016/S0040-4020(01)81433-2

According to the retrosynthetic perspective, the title total syntheses were accomplished by employing the regioselective Diels-Alder reactions of the (+)-naphthoquinone (5), the CDEF-ring system of nogalamycin congeners, with various structural types of dienes (8, 16, and 26).The highly functionalized dienes (16 and 26) incorporating all the functionalities present in the A-rings of (+)-7-deoxynogarol (3) and (+)-7-con-O-methylnogarol (2), were prepared efficiently by way of the 1,4-cyclohexadiene and 2-cyclohexanone derivatives (6 and 21), respectively.Reaction mechanism of the key Diels-Alder reaction was also discussed in terms of its stereoselectivity.