The cyclization of trimethylsilyl-substituted .alpha.-allenic alcohols to 3-(trimethylsilyl)-2,5-dihydrofurans and their facile autoxidation to 3-(trimethylsilyl)furans or 4-(trimethylsilyl)-2(5H)-furanones

Direct Synthesis of α‐Allenols from TMS‐Protected Alkynes and Aldehydes Mediated by Tetrabutylammonium Fluoride

“…This enhanced versatility afforded by the simultaneous presence of both functional entities is evident by their widespread use in organic chemistry . For example, they serve as key precursors for metal‐catalyzed cross‐couplings, and they are also widely employed in cycloaddition reactions catalyzed by Cu, Ru, Rh, Pd, Ag, Pt, and Au . As importantly, α‐allenols have been extensively used in the synthesis of natural products and heterocycles (e.g., pyrroles), in radical additions, for preparation of miscellaneous substituted dienes, in carbometallations, and in rearrangements to tune chemical properties.…”

“…This enhanced versatilitya ffordedbythe simultaneous presence of both functional entities is evident by their widespread use in organic chemistry. [2] For example, they serve as key precursors for metal-catalyzed cross-couplings, [2g, 3] and they are also widely employed in cycloaddition reactions catalyzed by Cu, [4] Ru, [5] Rh, [6] Pd, [7] Ag, [8] Pt, [9] and Au. [10] As importantly, a-allenols have been extensively used in the synthesis of natural products [11] and heterocycles( e.g.,p yrroles), [12] in radicala dditions, [13] for preparation of miscellaneous substituted dienes, [14] in carbometallations, [15] and in rearrangements [16] to tune chemical properties.D espite their significance,m ethods to prepare a-allenols, particularly under mild reactionc onditions that are compatible with ar ange of other functional groups,remain along-standing challenge.Established chemistry to generate a-allenols mostly relies on the use of hazardousa nd toxic metals, or synthetic equivalents such as activated allenes, as the source of coupling partners.…”

Bifunctionalized Allenes. Part XVI. Synthesis of 3-Phosphoryl-2,5-dihydrofurans by Coinage Metal-Catalyzed Cyclo-isomerization of Phosphorylated α-Hydroxyallenes

“…Transition metal-catalyzed cyclization of functionalized allenes bearing a nucleophilic center has attracted considearble attention in recent years [ 14 ]. Particularly, the cyclization reactions of allenols catalyzed by Ag(I) [ 15 , 16 , 17 , 18 ], Hg(II) [ 19 , 20 ], Pd(0) [ 21 , 22 , 23 ], Pd(II) [ 24 , 25 ], or Ru(III) [ 26 , 27 ] have become quite useful methodologies for the synthesis of five-, or six-membered oxygen-containing heterocycles. Krause’s group has reported a highly efficient and stereoselective synthesis of 2,5-dihydrofurans by Au(I)- and Au(III)-catalyzed [ 28 , 29 , 30 , 31 , 32 , 33 ] cycloisomerization of α-hydroxyallenes [ 34 , 35 , 36 ].…”

Silver-Catalyzed Cyclization of Sulfonyl Allenes to Dihydrofurans

“…Allenes bearing more complex substituents, particularly electron-withdrawing groups, have not been studied to any great extent in the context of metal ion-catalyzed cyclization to heterocycles. Wang studied allenyl silanes, and Lee examined allenyl esters in the context of gold- and copper-catalyzed cyclizations . It was only in 2015 that a silver-catalyzed cyclization of allenes bearing a group 15 electron-withdrawing group was published.…”