Premium
Synthesis of Carboxyl‐Tethered Symmetric Conjugated Polyenes as Fluorescent Transmembrane Probes of Lipid Bilayers
Author(s) -
Quesada Ernesto,
Acuña A. Ulises,
AmatGuerri Francisco
Publication year - 2003
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200390187
Subject(s) - chemistry , conjugated system , double bond , polyene , stille reaction , isomerization , fluorescence , triple bond , stereochemistry , coupling reaction , organic chemistry , polymer , catalysis , physics , quantum mechanics
The synthesis of a new series of fluorescent transmembrane probes in which two hydrophilic methyl ester or carboxyl groups are connected by a polymethylene chain, with four, five or six conjugated double bonds in a central position, is reported. The length of the linear structures was designed to match the width of typical lipid bilayers. These bolaamphiphilic compounds result, with overall yields higher than 80%, from an easy Pd II ‐catalyzed double cross‐coupling between terminal acetylene esters and conjugated 1,ψ‐dihalopolyenes, followed by selective triple bond partial reduction with activated zinc, and iodine isomerization to the all‐( E ) isomer. An alternative approach, based on a Stille double cross‐coupling between the appropriate all‐( E )‐ψ‐halopolyenes and ( E )‐bis(tributylstannyl)ethene, yielded mixtures that could not be resolved by standard chromatographic methods due to the presence of other simultaneous coupling reactions, which are also discussed in detail. Nevertheless, the Stille method can be of utility for the obtention of carbonyl‐polyene conjugated analogs. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003)