Beilstein J. Org. Chem.2013,9, 818–826, doi:10.3762/bjoc.9.93
be concluded that the observed divergentcyclization finds its origin in the initial 6-endo versus 6-exo oxyauration reaction steps, with the former being kinetically favored whereas the latter is thermodynamically favored. At this point, it cannot be safely discarded that the formation of the
PDF
Graphical Abstract
Scheme 1:
Preparation of allenic carbamates 2a–j. Reagents and conditions: (i) Propargylamine, MgSO4, CH2Cl2,...
Beilstein J. Org. Chem.2012,8, 930–940, doi:10.3762/bjoc.8.105
undertaken.
Keywords: chemical diversity; divergentcyclization; indole alkaloids; modular assembly; rhodium-catalyzed cyclization–cycloaddition; skeletal and stereochemical diversity; Introduction
Biologically intriguing natural products often possess cyclic scaffolds bearing dense arrays of functional
collections of the elaborated cyclic scaffolds, nature has evolved biosynthetic machinery and often employs (1) modular assembly and (2) divergentcyclization [4]. As the simplest example of this structural diversification, the biosynthesis of aromatic polyketides is outlined in Figure 1a. Employing acetyl
connection of simple building blocks, as well as divergentcyclization of a common precursor leading to distinct skeletons with complex molecular architectures.
Since the naturally occurring indole alkaloids share indole and piperidine as common substructures (Figure 1b) [6], we conceived the assembly of the
PDF
Graphical Abstract
Figure 1:
(a) Biosynthetic outline of aromatic polyketides; (b) structure of indole alkaloids composed of ind...