949009-86-3

Upstream product

• 1402464-10-1 (2S,3R,E)-tert-butyl 2-(((tert-butyldimethylsilyl)oxy)methyl)-4-ethylidene-3-methylpyrrolidine-1-carboxylate 
• 1402464-11-2 (2S,3R,E)-tert-butyl 4-ethylidene-2-formyl-3-methylpyrrolidine-1-carboxylate 
• 1402464-12-3 (2S,3R,E)-tert-butyl 4-ethylidene-2-(((S)-1-methoxy-4-methyl-1-oxopentan-2-yl)carbamoyl)-3-methylpyrrolidine-1-carboxylate 
• 1402464-13-4 (S)-methyl 2-((2S,3R,4E)-1-((S)-2-benzamido-6-(2,3-bis(tert-butoxycarbonyl)guanidino)hexanoyl)-4-ethylidene-3-methylpyrrolidine-2-carboxamido)-4-methylpentanoate?????? 
• 1360186-34-0 (7R,7aS,Z)-6-ethylidene-7-methyltetrahydropyrrolo[1,2-c]oxazol-3(1H)-one 
• 1402464-06-5 (7R,7aS,E)-6-ethylidene-7-methyltetrahydropyrrolo[1,2-c]oxazol-3(1H)-one 
• 1402464-02-1 (2S,3R,E)-tert-butyl4-ethylidene-2-(hydroxymethyl)-3-methylpyrrolidine-1-carboxylate 
• 1403324-66-2 (S)-tert-butyl 2-((2S,3R,E)-4-ethylidene-3-methylpyrrolidine-2-carboxamido)-4-methylpentanoate 
• 1403324-67-3 (S)-tert-butyl 2-((2S,3R,4E)-1-((S)-2-benzamido-6-(2,3-bis-(tert-butoxycarbonyl)guanidino)hexanoyl)-4-ethylidene-3-methylpyrrolidine-2-carboxamido)-4-methylpentanoate 

Relevant academic research and scientific papers

Total synthesis and structural revision of lucentamycin A

Lucentamycin A is a marine-derived peptide natural product harboring a unique 4-ethylidene-3-methylproline (Emp) subunit. The proposed structure of lucentamycin A and the core Emp residue have recently been called into question through synthesis. Here, we report the first total synthesis of lucentamycin A, which confirms that the ethylidene substituent in Emp bears an E geometry, in contrast to the originally assigned Z configuration. Synthesis of the desired (E)-Emp subunit required the implementation of a novel strategy starting from Garner's aldehyde.

Stereoselective total synthesis of the E-isomer of putative lucentamycin A

A synthesis of the E-isomer of the proposed structure of the novel tripeptide, lucentamycin A, was performed in an attempt to define the correct stereochemistry of this natural product. The synthetic route developed employs a stereoselective Rh-catalyzed reductive cyclization process to generate the key pyrrolidine residue in the target and a stereospecific inversion of the Z-olefin geometry to form desired E-isomer. Subsequent amide coupling reactions afforded the desired E-isomer of putative lucentamycin A. A comparison of the NMR data of synthetic E-1a with that of the naturally occurring lucentamycin A demonstrated that they are not identical substances and the E-1a was found to display no anti-proliferative activity on the colon cancer cell line HCT-116 in contrast to natural lucentamycin A.