Enyne Metathesis Catalyzed by Ruthenium Carbene Complexes

Abstract

Enyne metathesis combines an alkene and an alkyne into a 1,3-diene. The first enyne metathesis reaction catalyzed by a ruthenium carbene complex was reported in 1994. This review covers the advances in this transformation during the last eight years with particular emphasis on methodology development and synthetic applications. Concluding Remarks

NHC–Ru complexes—Friendly catalytic tools for manifold chemical transformations

“…The field of NHC-Ru catalyzed tandem and cascade reactions is vast comprising mostly combinations of: (i) different types of metathesis reactions (CM, RCM, ROM, RCEYM, ROMP, etc.) [112]; (ii) metathetical/non-metathetical transformations (this chapter; see also: Morita-Baylis-Hillman reaction/RCM for synthesis of functionalized hetero-and carbocyclic alkenols [113], allylation/RCM on reaction products from a Ugi four-component coupling towards cyclized peptidomimetics with various appendages [114], and sequential or tandem metathesis/Diels-Alder [115]; (iii) various non-metathetical steps (e.g. tandem isomerization/Claisen rearrangement [116a], diastereo-and enantioselective cyclization [116b], etc.)…”

Synthesis of fluorinated δ-lactams via cycloisomerization of gem-difluoropropargyl amides

“…We postulated that functionalized fluorinated enyne amides could be used for the synthesis of a chemically diverse suite of δ-lactams because enynes are suitable partners in ring-closing metathesis reactions or cycloisomerizations. An additional benefit of using enynes in metathesis reactions is that the resulting diene product could be further elaborated using a Diels–Alder reaction to construct bi- or tricyclic ring systems [20]. …”

A DFT study on the reaction mechanism of the gold(I)‐catalyzed cycloisomerization of alkynylhydroxyallylamides to 4‐Oxa‐6‐azatricyclo[3.3.0.02,8]octane and 3‐Acyl‐4‐alkenylpyrrolidine

“…The mechanism of Au(I)-catalyzed cycloisomerization of 1,6-enynes through DFT calculations has been well studied by a number of scientists [12][13][14][15][16][17][18][19][20][21][22][23][24]. Representative reaction pathways include 5-exo-dig and 6-endo-dig cyclizations, from which a variety of subsequent reactions can proceed.…”