Linked Pummerer-Mannich Ion Cyclizations for Heterocyclic Chemistry
- Resource Type
- Authors
- Scott K. Bur; Diana M. Danca; Albert Padwa; Stephen M. Lynch; John D. Ginn
- Source
- Synlett. 2002:0851-0862
- Subject
- Chemistry
Intramolecular force
Pummerer rearrangement
Organic Chemistry
Molecule
Sequence (biology)
Ring (chemistry)
Mannich reaction
Combinatorial chemistry
Diels–Alder reaction
Ion
- Language
- ISSN
- 1437-2096
0936-5214
Sequential transformations enable the facile synthesis of complex target molecules from simple building blocks in a single preparative step. As part of a program concerned with new methods for alkaloid synthesis, we have been utilizing a linked Pummerer/N-acyliminium ion cyclization sequence because this combination offers unique opportunities for the assemblage of complex target molecules. Cyclic 2-methylthio-5-amidofurans possessing tethered rebonds were prepared from various amido dithioacetals. Upon heating, these systems undergo an intramolecular 4+2-cycloaddition reaction. The initially formed Diels-Alder cycloadduct further rearranges by ring opening of the oxygen bridge followed by a subsequent 1,2-methylthio shift. The method has been successfully applied to several different families of alkaloids.