Antonietta Rose Mastrocola

Novel syntheses of camptothecin alkaloids, part I. Intramolecular [4+2] cycloadditions of N-arylimidates and 4H-3,1-benzoxazin-4-ones as 2-aza-1,3-dienes

Abstract The first reported intramolecular [4+2] cycloadditions of both N-arylimidates and 4 H -3,1-benzoxazin-4-ones acting as 2-aza-1,3-dienes are described. Reaction with unactivated alkynes leads to pyrrolo[3,4-b]quinolines which constitute the ABC ring system of camptothecins.

Novel syntheses of camptothecin alkaloids, part 2. concise synthesis of (S)-camptothecins

Abstract A 9-step, convergent total synthesis of ( S )-camptothecin alkaloids is described. The intramolecular [4+2] cycloaddition of an N-arylimidate with an alkyne is used to prepare the alkaloid ABC ring system. 1 The chiral center is derived utilizing Seebachs chemistry 2 for the diastereoselective Michael addition of a chiral dioxolanone enolate to a methylene malonate acceptor. The total synthesis of non-racemic topotecan is accomplished from (S)-10-hydroxycamptothecin in an additional step.

Preparation of mappicine ketones from camptothecins : chemistry of the camptothecin E ring

Abstract Camptothecin and its analogs are thermolyzed at 150–200 °C to yield mappicine ketone derivatives by loss of carbon dioxide from the α-hydroxylactone.