Design and implementation of an efficient synthetic approach to pyranosylated indolocarbazoles: Total synthesis of (+)-RK286c, (+)-MLR-52, (+)-staurosporine, and (-)-TAN-1030a

A total synthesis of the natural products (+)-staurosporine (2), (+)-RK286e (3), (-)-TAN-1030a (4), and (+)-MLR-52 (5) has been achieved. The synthetic strategy involves the stereoselective ring expansion of a furanosylated indolocarbazole [(+)-8] to a pyranosylated congener [(+)-12] that serves as a common intermediate in the production of 2-5.