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Synthesis of an Epoxide‐ and Carbonate‐Containing 6‐/10‐Membered Bicyclodienediyne Analogue of the Neocarzinostaitin Chromophore
Author(s) -
Ferri Fabiola,
Brückner Reinhard
Publication year - 1997
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199719970527
Subject(s) - chemistry , chromophore , neocarzinostatin , epoxide , diol , stereochemistry , aldehyde , enediyne , sharpless epoxidation , yield (engineering) , carbonate , organic chemistry , catalysis , materials science , metallurgy , dna , biochemistry
The monocyclo‐diendiyne → bicyclo‐trienediyne strategy for obtaining dienediyne models of the antitumor antibiotic neocarzinostatin chromophore ( 1 ) was extended from generating 6‐/11‐membered bicyclotrienediynes (e.g. 2 → 4 ) to generating the 6‐/10‐membered bicyclotrienediyne 5 . In the preparatory steps (Scheme 2), the bistriflate 10 was successively coupled with alkynes 9 and 11 . Via the dienediynediol and its subsequent oxidation with the Dess‐Martin periodinane, we obtained the monocyclic dienediyne keto aldehyde 13 . Cyclization of 13 with low‐valent titanium afforded the bicyclotrienediyne 5 in 42% yield (Scheme 3). Compound 5 was converted in five steps – namely ketal cleavage, monosilylation of the resulting diol 14 , asymmetric Sharpless epoxidation, desilylation and carbonate formation – into the dienediyne epoxycarbonate 3 . The structure of the latter is more closely related to the neocarzinostatin chromophore than our earlier analogues.