474886-89-0Relevant academic research and scientific papers
Efficient macrocyclization by means of 2-nitrobenzenesulfonamide and total synthesis of lipogrammistin-A
Kan, Toshiyuki,Fujiwara, Akiko,Kobayashi, Hideki,Fukuyama, Tohru
, p. 6267 - 6276 (2007/10/03)
Synthesis of medium- and large-sized cyclic amines using alkylation with 2-nitrobenzenesulfonamides is described. Using either conventional alkylation procedures or Mitsunobu conditions, the cyclization reaction proceeded in a highly efficient manner. The usefulness of this methodology has been fully demonstrated in the total synthesis of lipogrammistin-A (9), an 18-membered cyclic polyamine.
Total synthesis of lipogrammistin-A: Efficient macrocyclization with 2-nitrobenzenesulfonamide
Fujiwara,Kan,Fukuyama
, p. 1667 - 1669 (2007/10/03)
Total synthesis of lipogrammistin-A (1) was accomplished using a 2-nitrobenzenesulfonyl (Ns) group for both protection and activation of amines. The β-amino ester derivative 16 was synthesized from carboxylic acid 12 in six steps by way of reduction to the aldehyde and the subsequent Wittig olefination. N-Alkylation of the Ns group under Mitsunobu conditions followed by amide formation provided 20. Intramolecular alkylation of the Ns group in 20 gave the 18-membered ring 21 as the exclusive product. After removal of the Ns group, selective acylation of the two of the three amino groups with (S)-2-methylbutyric acid furnished the desired compound 1.
