(E)-Cycloalkenes and (E,E)-cycloalkadienes by ring closing diyne- or enyne–yne metathesis/semi-reduction

Autor: Alois Fürstner, Günter Seidel, Fabrice Lacombe, Karin Radkowski
Rok vydání: 2004
Předmět:
Zdroj: Tetrahedron. 60:7315-7324
ISSN: 0040-4020
DOI: 10.1016/j.tet.2004.05.042
Popis: A concise, practical and stereoselective entry into macrocyclic (E)-alkenes is outlined comprising a sequence of ring closing alkyne metathesis (RCAM), trans-selective hydrosilylation of the resulting cycloalkynes catalyzed by [Cp∗Ru(MeCN)3]PF6, and a protodesilylation of the ensuing vinylsilanes with AgF in aq. THF/MeOH. Moreover, the first examples of intramolecular enyne–yne metathesis reactions catalyzed by the Schrock alkylidyne complex (tBuO)3WCCMe3 are reported; the resulting cyclic enynes can be converted along similar lines into the corresponding (E,E)-configured 1,3-dienes in good overall yields. Cycloalkyne 4 and the (E)-configured cyclic olefins 6 and 21 were characterized by X-ray crystallography.
Databáze: OpenAIRE