| abstract |
The present invention provides a short, convergent total synthesis of irinotecan and derivative compounds which comprises a novel 4 + 1 radical annulation wherein the precursor (I) is reacted with an aryl isonitrile having the formula (II) wherein X is Br or I, and R4 is an alkyl group, an allyl group, a propargyl group or a benzyl group, and R16 is H, a C¿1?-C6 alkoxy group, a (a) group wherein p is an integer between 4 and 12, or a C1-C12 acyclic dialkylamino group. The present invention also provides novel chemical intermediates for such 4 + 1 radical annulations. |