Heterocycles

Synthetic studies of heterocyclic structural motifs in natural products have been a longstanding interest. These studies have led to the development of methodology and various applications for natural product synthesis. Several examples are summarized as follows:

A) The preparation of substituted oxazole by site-selective deprotonation and nucleophilic substitution.

meth3A

Primary references: Org. Lett. 2010, 12, 808-811.
Barbier reactions of ɑ-iodomethylheterocycles: Org. Lett. 2005, 7, 4099-4102.
Imidazoles: Tet. Lett. 1997, 38, 7835-7838.
Ring metalation of [2,4]-bisoxazoles: Tet. Lett. 1998, 39, 8023-8026.

B) The formation of oxazoles and thiazoles by dehydration and oxidation:

meth3B

Primary references: Org. Lett. 2000, 2, 3023-3026.
Application for hennoxazole synthesis: J. Am. Chem. Soc. 1999, 121, 4924-4925.

C) Substituted 1,3-oxazoles via the Halogen Dance Reaction and selective cross-coupling reactions

meth3C

Primary references: Synlett 2010, 591-594; Synlett 2010, 1641-1646.

D) Preparation of 3,5-disubstituted-2(1H) pyridinones

meth3D

Primary references: Heterocycles 2006, 67, 555-559.
Applications to Apiosporamide: Angew. Chem. Int. Ed. 2005, 44, 6715-6718.
Construction of 4-Hydroxy-2-pyridinones: Org. Lett. 2000, 2, 3217-3220.
Studies of Dimethylfuniculosin: Tet. Lett. 2000, 41, 9397-9401.

E) Mild dehydrogenations in heterocyclic systems

meth3E

Primary reference: Tet. Lett. 1997, 38, 331-334.

F) Preparation of C-4 thiazole phosphonium methylides

meth3F

Primary reference: Tet. Lett. 1996, 37, 983-986.

G) Synthesis of complex 1,3-oxazoles via the Cornforth Rearrangement

meth3G

Primary reference: Tet. Lett. 1993, 34, 7705-7708.