Meeting the Challenge of Intermolecular Gold(I)‐Catalyzed Cycloadditions of Alkynes and Allenes

Abstract

The development of gold(I)-catalyzed intermolecular carbo- and hetero-cycloadditions of alkynes and allenes has been more challenging than their intramolecular counterparts. Here we review, with a mechanistic perspective, the most fundamental intermolecular cycloadditions of alkynes and allenes with alkenes.

Gold‐Catalyzed Formal [4+1]/[4+3] Cycloadditions of Diazo Esters with Triazines

“…[4] In contrast, the use of gold complexes in such reactions remains less well investigated. [10] Recently,K rische and co-workers developed as eries of novel ruthenium-catalyzed hydroaminomethylations by using hexahydro-1,3,5-triazines as precursors of N-aryl formaldimines (Scheme 1a). [10] Recently,K rische and co-workers developed as eries of novel ruthenium-catalyzed hydroaminomethylations by using hexahydro-1,3,5-triazines as precursors of N-aryl formaldimines (Scheme 1a).…”

Gold‐catalyzed [4+2] Annulations of Dienes with Nitrosoarenes as 4 π Donors: Nitroso‐Povarov Reactions

“…Thep roducts 3 correspond to the annulations with the tetrasubstituted alkenes of the dienes 1' ',w hereas 3' ' arises from the trisubstituted alkenes.W et ested the [4+ +2] annulations on various C1-aryl-substituted vinylallenes (1b-e;X= Me,OMe,Brand Cl), giving the compounds 3b-e in satisfactory yields (entries 1-4). With R 1 = phenyl, we varied either the R 2 or R 3 of the vinylallenes 1m-o with alkyl groups, and the resulting products 3m-o were also produced satisfactorily with 59-68 %yields (entries [12][13][14]. For 1i,bearing R 1 = 2-naphthyl, its resulting product 3i was produced smoothly and structurally characterized by X-ray diffraction.…”

Diastereospecific Gold(I)‐Catalyzed Cyclization Cascade for the Controlled Preparation of N‐ and N,O‐Heterocycles

“…Gold(I) catalysis has been used to prepare N,O‐heterocycles by reaction of amides and hydroxylamine with alkynes and allenes and it is well recognized that electrophilic gold(I) catalysts are powerful mediators for the cycloisomerization of 1, n ‐enynes and their trapping with various nucleophiles . Although there is a wealth of work in this area, we identified that there were still untapped opportunities in the trapping of transient cyclopropyl‐gold(I) carbenes with oximes.…”

“…Gold(I) catalysis has been used to prepareN ,O-heterocycles by reactiono fa mides [19] and hydroxylamine [20] with alkynes and allenes andi ti sw ell recognized that electrophilic gold(I) catalysts are powerful mediators for the cycloisomerizationo f 1,n-enynesa nd their trappingw ithv arious nucleophiles. [21][22][23][24][25][26][27][28][29][30] Althought here is aw ealth of work in this area, we identified that there were still untapped opportunities in the trapping of transientc yclopropyl-gold(I) carbenes with oximes. We reasoned that these species should behave as ambivalent nucleophiles, and depending on their configuration, should lead selectively to N-or O-cyclizedc ompounds.…”