1,6-Enynes with electron-donating substituents at the alkyne undergo gold(I)-catalysed single cleavage skeletal rearrangement, whereas substrates with electron-withdrawing substituents evolve selectively to double cleavage rearrangement. Theoretical calculations provide a qualitative rationale for these effects, and suggest that bicyclo[3.2.0]hept-5-enes are involved as intermediates. We provide the first X-ray structural evidence for the formation of a product of this class in a cycloisomerisation of a 1,6-enyne.

No abstract

Gold and rings: The gold(I)-catalyzed addition of aldehydes to 1,6-enynes gives 1,3-dienes, by a cycloaddition/fragmentation process. 1,5-Enynes react with aldehydes and ketones by the 5-endo-dig pathway to give the corresponding cycloadducts.

As the field of supramolecular catalysis develops, a sound fundamental understanding of the catalytic assemblies used will be essential. There is a lack of knowledge regarding systems based on transition‐metal catalysts as guests of supramolecular capsules. We investigate the inclusion behavior of gold complexes based on well‐known cationic Au(I) catalysts within a self‐assembled hexameric resorcin[4]arene capsule. The results shed light on the nature of the encapsulated species and the way in which those species are encapsulated. We introduce an encapsulation methodology that functions through the transient introduction of an excess of water. Through small modifications in the encapsulation methodology, we show that the inclusion process can be controlled to give different encapsulated species stemming from the same gold(I) precursor.

This chapter reviews the gold‐catalyzed cyclization reactions of alkynes with alkenes that proceed via selective activation of the alkyne by π‐coordination of the transition metal. Mechanistically related intermolecular reactions between alkynes and alkenes are also discussed, as are reactions of alkynes with arenes, heteroarenes, and related nucleophiles.

The gold‐catalyzed rearrangement of 1,6‐ and 1,7‐enynes is studied.

Ring closure reactions O 0130Gold-Catalyzed Reactions of 1,5-and 1,6-Enynes with Carbonyl Compounds: Cycloaddition vs. Metathesis. -1,5-Enynes react with aldehydes and ketones via a 5-endo-dig pathway to give the corresponding cycloadducts. For substrates with aryl substituents at the alkyne [cf. (XXIII)], an unprecedented fragmentation takes place to give products of type (XXV). -(ESCRIBANO-CUESTA, A.; LOPEZ-CARRILLO, V.; JANSSEN, D.; ECHAVARREN*, A. M.; Chem. Eur. J. 15 (2009) 23, p5646-p5650; Inst. Chem. Res. Catalonia, E-43007 Tarragona, Spain; Eng.) -Bartels 40-031

Ring closure reactions O 0130Gold-Catalyzed Reactions of 1,5-and 1,6-Enynes with Carbonyl Compounds: Cycloaddition vs. Metathesis. -The addition of aldehydes to 1,6-enynes gives 1,3-diene metathesis products and in some cases also the expected cycloaddition products (to be continued). -(ESCRIBANO-CUESTA, A.; LOPEZ-CARRILLO, V.; JANSSEN, D.; ECHAVARREN*, A. M.; Chem. Eur. J. 15 (2009) 23, 5646-5650; Inst. Chem. Res. Catalonia, E-43007 Tarragona, Spain; Eng.) -Bartels 40-030