Document Detail

A total synthesis of (-)-hemiasterlin using N-Bts methodology.
MedLine Citation:
PMID:  11681948     Owner:  NLM     Status:  MEDLINE    
A total synthesis of (-)-hemiasterlin has been accomplished in nine steps from 25(8) (>35% yield overall). An improved enantiocontrolled route to the tetramethyltryptophan subunit 32 was developed using an asymmetric Strecker synthesis (five steps, 50% yield from 25), and the dipeptide 22 was prepared in seven steps, 37% yield from valinol. The synthesis exploits the high reactivity of a Bts-protected amino acid chloride in the difficult peptide coupling of sterically hindered amino acid residues 18 and 20 to form 21 (70%, recrystallized) and also uses N-Bts intermediates for the high-yielding N-methylations of 14 and 31. In addition, the Bts-protected di-tert-butyl N-acylimidodicarbonate 33 is shown to undergo efficient coupling with 22 to form 34 (97% in the coupling step; 79% over the activation; coupling sequence from 32).
E Vedejs; C Kongkittingam
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The Journal of organic chemistry     Volume:  66     ISSN:  0022-3263     ISO Abbreviation:  J. Org. Chem.     Publication Date:  2001 Nov 
Date Detail:
Created Date:  2001-10-29     Completed Date:  2002-03-12     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  2985193R     Medline TA:  J Org Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  7355-64     Citation Subset:  IM    
Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, USA.
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MeSH Terms
Antineoplastic Agents / chemical synthesis*
Oligopeptides / chemical synthesis*
Porifera / chemistry
Grant Support
Reg. No./Substance:
0/Antineoplastic Agents; 0/Oligopeptides; 0/hemiasterlin A; 0/hemiasterlin B; 0/hemiasterlin C

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