Fukuyama, Okano and Tokuyama. JACS, 2006, 128(22), 7136. DOI: 10.1021/ja0619455
Continuing somewhat with a heterocyclic theme, Fukuyama has published a short (20 steps), flexable and rather sweet (13% yield) synthesis of yakatemycin. Especially interesting is his use of a ring contraction to put in the cyclopropane; being a spirocyclopropane, this is a reactive beast, so his strategy is rather nice:
Completed as the final step in the synthesis, one can imagine several fingers were crossed during the reaction! This paper also includes the use of an azide displacement / Staudinger reaction to create a ÃŸ-hydroxy amine from a chlorohydrin. Monoprotection of the amine with a nosyl group then allowed them to complete a ring-closing amination.
Althougth the nosyl group is fairly well known, I thought I’d show it in full: