title: Total syntheses of bengamides B and E.
abstract: Total syntheses of the cytotoxic marine natural products bengamides B and E are described. Both bengamides are prepared via amide coupling of a protected polyhydroxylated lactone intermediate 9 with a suitably substituted aminocaprolactam intermediate. Lactone 9 is prepared in five steps from commercially available alpha-D-glucoheptonic gamma-lactone. The key reactions are a selective deprotection of a 1,2-acetonide in the presence of a 1,3-acetonide and an (E)-selective olefination of an unstable aldehyde using a gem-dichromium reagent. The bengamide B lactam intermediate 10 is prepared in seven steps from commercially available (5R)-5-hydroxy-L-lysine (12). The desired S-configuration at the gamma-OH lactam position is established using the Mitsunobu reaction.
authors: Oncology Department, Novartis Pharmaceuticals Corporation, 556 Morris Avenue, Summit, New Jersey 07901, USA. frederick.kinder@pharma.novartis.com
authors: F R
authors: FR
authors: Kinder
authors: S
authors: S
authors: Wattanasin
authors: R W
authors: RW
authors: Versace
authors: K W
authors: KW
authors: Bair
authors: J
authors: J
authors: Bontempo
authors: M A
authors: MA
authors: Green
authors: Y J
authors: YJ
authors: Lu
authors: H R
authors: HR
authors: Marepalli
authors: P E
authors: PE
authors: Phillips
authors: D
authors: D
authors: Roche
authors: L D
authors: LD
authors: Tran
authors: R
authors: R
authors: Wang
authors: L
authors: L
authors: Waykole
authors: D D
authors: DD
authors: Xu
authors: S
authors: S
authors: Zabludoff
mesh_terms: D000818:Animals; D001381:Azepines / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D013058:Mass Spectrometry; D015394:Molecular Structure; D011161:Porifera / Q000737:chemistry
chemical_list: D001381:Azepines; C427480:bengamide B; C427481:bengamide E