Butatriene durch Cumuhomologisierung von Propadienen

Abstract

Wer hätte das gedacht? In nur vier Stufen erhält man ausgehend von kommerziell erhältlichen Alkinolen acceptorsubstituierte Butatriene 1 in guten Gesamtausbeuten. Im wichtigsten Schritt der Synthese werden Allene einfach „verlängert”︁ .

Ambivalent Reactivity Modes of β‐Chlorovinyl Ketones: Electrophilic Lithium [3]Cumulenolates from Soft Vinyl Enolization Strategy

“…In contrast, the reactivity behavior of [n]cumulene derivatives, compounds with three or more consecutive double bonds, has not been fully explored because of the difficulty associated with their preparation other than tetrasubstituted [3]cumulene derivatives 4. While a limited number of acyl‐substituted [3]cumulene derivatives are known to be stable5 and subsequently utilized in the enyne cycloaddition,6 palladium‐catalyzed arylation,7 Lewis acid catalyzed Diels–Alder reactions,8 phosphine‐9 and silver‐catalyzed [3+2] cycloaddition reactions,10 the synthesis as well as synthetic utility of donor‐substituted [3]cumulene derivatives have yet to be established 11…”

Laser‐induced desorption of small molecules from oxide surfaces: A first‐principles study

“…Details of this study can be found in ref 86. As another control strategy allowing for the manipulation of final state distributions in DIET processes, vibrationally mediated photochemistry for the system NH 3 /Cu (111) has been investigated in a two-dimensional scenario. 41,44,115 It was proposed to excite the umbrella mode of the adsorbed ammonia molecule by an infrared pulse and subsequently desorb the molecule by a UV-laser pulse. This two-pulse strategy also results in an enhanced desorption probability.…”

Ambivalent Reactivity Modes of β‐Chlorovinyl Ketones: Electrophilic Lithium [3]Cumulenolates from Soft Vinyl Enolization Strategy

“…[2,3] Thus, donor/acceptor-substituted allenes have emerged among the most versatile synthetic building blocks in the development of novel carbon-carbon bond-forming reactions (Scheme 1). [4] While a limited number of acyl-substituted [3]cumulene derivatives are known to be stable [5] and subsequently utilized in the enyne cycloaddition, [6] palladium-catalyzed arylation, [7] Lewis acid catalyzed Diels-Alder reactions, [8] phosphine- [9] and silvercatalyzed [3+2] cycloaddition reactions, [10] the synthesis as well as synthetic utility of donor-substituted [3]cumulene derivatives have yet to be established. [4] While a limited number of acyl-substituted [3]cumulene derivatives are known to be stable [5] and subsequently utilized in the enyne cycloaddition, [6] palladium-catalyzed arylation, [7] Lewis acid catalyzed Diels-Alder reactions, [8] phosphine- [9] and silvercatalyzed [3+2] cycloaddition reactions, [10] the synthesis as well as synthetic utility of donor-substituted [3]cumulene derivatives have yet to be established.…”

“…In contrast, the reactivity behavior of [n]cumulene derivatives, compounds with three or more consecutive double bonds, has not been fully explored because of the difficulty associated with their preparation other than tetrasubstituted [3]cumulene derivatives. [4] While a limited number of acyl-substituted [3]cumulene derivatives are known to be stable [5] and subsequently utilized in the enyne cycloaddition, [6] palladium-catalyzed arylation, [7] Lewis acid catalyzed Diels-Alder reactions, [8] phosphine- [9] and silvercatalyzed [3+2] cycloaddition reactions, [10] the synthesis as well as synthetic utility of donor-substituted [3]cumulene derivatives have yet to be established. [11] Recently, we reported a facile a-vinyl enolization pathway of (E)-b-chlorovinyl ketones in which transient oxy-substituted [3]cumulene derivatives [i.e., cumulenol(ate)s] were postulated as nucleophilic species, reacting either with a protic source [12] or aldehydes [13] (Scheme 2).…”