Download PDF
Synthesis 2000; 2000(4): 588-602
DOI: 10.1055/s-2000-6366
feature article
© Georg Thieme Verlag, Rüdigerstr. 14, 70469 Stuttgart, Germany. All rights reserved. This journal, including all individual contributions and illustrations published therein, is legally protected by copyright for the duration of the copyright period. Any use, exploitation or commercialization outside the narrow limits set by copyright legislation, without the publisher's consent, is illegal and liable to criminal prosecution. This applies in particular to photostat reproduction, copying, cyclostyling, mimeographing or duplication of any kind, translating, preparation of microfilms, and electronic data processing and storage.

β-Alkoxycarbonyl Enol Triflates as Precursors of Stereopure 3-Ene-1,5-diyne Building Blocks for the Chromophores of Neocarzinostatin, C-1027, Kedarcidin, Maduropeptin, and N1999A2

Olaf Gebauer* , Reinhard Brückner
  • *Geschäftsbereich Pflanzenschutz, BAYER-AG, PF-F-S1 Fungizide, Alfred-Nobel-Str. 50, 40789 Monheim, Germany; Fax +49 (21 73) 38 39 26; E-mail: olaf.gebauer.og@bayer-ag.de
Further Information

Publication History

Publication Date:
31 December 2000 (online)

  PDF Download  Permissions and Reprints All articles of this category

A 5-step synthesis of α-alkoxymethyl-, α-siloxymethyl- and α-(carbamoyloxy)methyl-substituted enediynes 7 from type 23 β-oxo esters was developed following the strategy of Scheme 2. Specifically, the β-oxo esters 33, 36 and 38 (prepared as shown in Scheme 4) and NaH (or t-BuLi) gave Z-enolates in THF and E-enolates in DMF which were scavenged as enol triflates Z-27a-c and E-27a-c, respectively, upon treatment with triflimides 40 or 41 (Scheme 5). The Z-configurated enol triflates underwent Cacchi couplings with (trimethylsilyl)acetylene to give the pent-2-en-4-yne-1-carboxylates E-42a-c (Scheme 5). These were reduced to the corresponding aldehydes E-44a-c (Scheme 6) which were homologated with lithio(trimethylsilyl)diazomethane to furnish the desired enediynes 45a-c as pure E-isomers.

C-C couplings - enediynes - enynes - β-oxo esters - stereoselective enolate formation