Carotenoids and related polyenes. Part 4.1 Synthesis of carotenoid analogues containing a conjugated carbonyl group and their fluorescence properties
作者:Yumiko Yamano、Mamoru Mimuro、Masayoshi Ito
DOI:10.1039/a702815f
日期:——
Fluorescence properties of several synthetic carotenoid analogues
have been investigated in order to assess the relationship between
molecular structures and function as a photosynthetic antenna. The
origin of fluorescence is determined by two factors; the length of the
conjugated double bond system and the presence of a carbonyl group. For
efficient energy transfer to chlorophyll a, eight conjugated
double bonds and an associated carbonyl group are required, which
ensures that fluorescence occurs from the S1 state.
Chemo-, Regio-, and Stereoselective Silver-Catalyzed Aziridination of Dienes: Scope, Mechanistic Studies, and Ring-Opening Reactions
作者:Josep Llaveria、Álvaro Beltrán、W. M. C. Sameera、Abel Locati、M. Mar Díaz-Requejo、M. Isabel Matheu、Sergio Castillón、Feliu Maseras、Pedro J. Pérez
DOI:10.1021/ja412547r
日期:2014.4.9
of 2,4-diene-1-ols in a chemo-, regio-, and stereoselective manner to give vinylaziridines in high yields by means of the metal-mediated transfer of NTs (Ts = p-toluensulfonyl) units from PhI═NTs. The preferential aziridination occurs at the double bond neighboring to the hydroxyl end in ca. 9:1 ratios that assessed a very high degree of regioselectivity. The reaction with the silver-based catalysts
Synthesis, Structure, and Reactivity of Alkyl-Substituted Half-Sandwich η<sup>5</sup>-Pentadienyl Complexes of Cobalt
作者:Kai E. O. Ylijoki、Ross D. Witherell、Andrew D. Kirk、Sebastian Böcklein、Verner A. Lofstrand、Robert McDonald、Michael J. Ferguson、Jeffrey M. Stryker
DOI:10.1021/om900754h
日期:2009.12.14
Alkyl-substituted η5-pentadienyl complexes of cobalt have been reported to undergo [5 + 2] cycloaddition reactions with alkynes to form substituted η2,η3- and η5-cycloheptadienyl products, providing a new route to the synthesis of substituted cycloheptadienes. A series of cyclopentadienyl and pentamethylcyclopentadienyl cobalt(III) η5-pentadienyl complexes have been prepared, incorporating alkyl and
Rhodium-Catalyzed Synthesis of Eight-Membered Rings
作者:Brenton DeBoef、W. Richard Counts、Scott R. Gilbertson
DOI:10.1021/jo0620462
日期:2007.2.1
Experiments to develop a rhodiumcatalyst for the [4 + 2 + 2] cycloisomerization of dienynes with a second alkyne are described. The generality of the reaction is probed in terms of dienyne structure and alkyne structure. A catalystsystem that provides cyclooctatrienes in greater than 70% yield is reported. Several experiments to determine the nature of the catalyst are described.