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Abstract: A novel reaction that provides chiral allenes by amino catalytic activation of either aldehydes or α,β‐unsaturated aldehydes for reaction with alkynyl‐substituted enones is presented. The reaction forms a variety of trisubstituted allenes in high yields and with excellent stereoselectivities. The utility of the reaction concept is demonstrated by the synthesis of chiral furan derivatives in high yields and stereoselectivities. [ABSTRACT FROM AUTHOR]

The diastereoselective gold(I) catalysed cyclisation of highly substituted aminoallene derivatives allows the synthesis of both epi -DAB-1 and di- epi -lentiginosine. While the sense of stereoselectivity observed is in line with earlier observations on analogous piperidine-forming cyclisations, different ligands and reaction conditions are required to obtain good yields. [ABSTRACT FROM AUTHOR]

A stereoselective nickel-catalyzed [2+2] cycloaddition of ene-allenes is reported. This transformation encompasses a broad range of ene-allene substrates, thus providing efficient access to fused cyclobutanes from easily accessed π-components. A simple and inexpensive first-row catalytic system comprised of [Ni(cod)2] and dppf was used in this process, thus constituting an attractive approach to synthetically challenging cyclobutane frameworks under mild reaction conditions. [ABSTRACT FROM AUTHOR]

The present review is focused on the application of computational/theoretical methods to the wide and rich chemistry of allenes. Special emphasis is made on the interplay and synergy between experimental and computational methodologies, rather than on recent developments in methods and algorithms. Therefore, this review covers the state-of-the-art applications of computational chemistry to understand and rationalize the bonding situation and vast reactivity of allenes. Thus, the contents of this review span from the most fundamental studies on the equilibrium structure and chirality of allenes to recent advances in the study of complex reaction mechanisms involving allene derivatives in organic and organometallic chemistry. [ABSTRACT FROM AUTHOR]

Natural antifouling products have been the subject of considerable attention. We screened marine algae for antifouling activity and discovered omaezallenes, the new bromoallene-containing natural products isolated from the red alga Laurencia sp. Described is the isolation, structure elucidation, and total syntheses of omaezallenes. The relative and absolute configurations of natural omaezallenes were unambiguously established through total synthesis. The antifouling activities and ecotoxicity of omaezallenes were also evaluated. [ABSTRACT FROM AUTHOR]

Eine solide Grundlage: 2 ‐ Boryl ‐ 1,3 ‐ butadiene mit verschiedenen Substitutionsmustern wurden in guten bis hohen Ausbeuten in einer Kupfer ‐ katalysierten Borylierung von α ‐ Alkoxyallenen mit Bis(pinakolato)dibor gebildet (siehe Schema; Bn=Benzyl, pin=Pinakolat, L ist ein N ‐ heterocyclisches Carben). Die Produkte sind nützliche Zwischenstufen für die Synthese von cyclischen Vinylboranen, α,β ‐ ungesättigten Ketonen und funktionalisierten mehrfach substituierten Dienen. [ABSTRACT FROM AUTHOR]