Gold-Catalyzed Cycloisomerization of 1,6-Diyne Esters to 1H-Cyclopenta[b]naphthalenes, cis-Cyclopenten-2-yl δ-Diketones, and Bicyclo[3.2.0]hepta-1,5-dienes

Abstract

A synthetic method to chemoselectively prepare 1H-cyclopenta[b]naphthalenes, cis-cyclopenten-2-yl δ-diketones, and bicyclo[3.2.0]hepta-1,5-dienes efficiently by gold-catalyzed cycloisomerization of 1,6-diyne esters is described. These three product classes were accessed divergently by taking advantage of the electronic and steric differences between a phosphine and NHC (NHC = N-heterocyclic carbene) ligand in the respective gold(I) complexes and that of gold(III) complex combined with substrate substitution patterns and optimized reaction conditions. In the presence of [PhCNAuIPr](+)SbF6(-) (IPr = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidine) as the catalyst, substrates with a pendant aryl group at the acetate alkynyl position were found to undergo preferential 1,3-acyloxy migration/5-exo-dig cyclization/Friedel-Crafts reaction to give 1H-cyclopenta[b]naphthalenes. In contrast, the analogous reactions with PicAuCl2 (Pic =2-picolinate) were found to proceed by selective 1,3-acyloxy migration/5-exo-dig cyclization/1,5-acyl migration to afford cis-cyclopenten-2-yl δ-diketones. Changing the catalyst to [MeCNAu(JohnPhos)](+)SbF6(-) (JohnPhos = (1,1'-biphenyl-2-yl)-di-tert-butylphosphine) and the acetate alkynyl position from an aryl to vinyl substituent in the starting ester led to 1,3-acyloxy migration/5-exo-dig cyclization/Prins-type [2 + 2]-cycloaddition to provide bicyclo[3.2.0]hepta-1,5-dienes.

Triazole acetyl gold(III) catalyzed Meyer–Schuster rearrangement of propargyl alcohols

“…7 Chan group showed that PicAuCl 2 catalyzed selective 1,3acyloxy migration/5-exo-dig cyclization/1,5-acyl migration to afford cis-cyclopenten-2-yl δ-diketones. 8…”

Insights into the Gold‐Catalyzed Propargyl Ester Rearrangement/Tandem Cyclization Sequence: Radical versus Gold Catalysis—Myers–Saito‐ versus Schmittel‐Type Cyclization

“…[8] In the case of agold-catalyzed 1,3-acylshift, carboxyallenes are generated that can act as an ucleophile [9] or electrophile [10] for furtherapplications in tandemreactions. [11,12] To ste et al and Oh and Kim et al combinedasilver or goldcatalyzedallene formation by 1,3-acyl migration of nonterminal propargylic esters with aM yers-Saito-type enyne-allene cyclizationt of orm highly functionalized aromatic compounds (Scheme 1a). [9e, 11p] Liu et al publishedasimilarr eactionu sing propargyl carbonatesi nsteado ft he correspondinge sters.…”

Gold‐Catalyzed Sequential Cyclization of 1‐En‐3,9‐Diyne Esters to Partially Hydrogenated 3H‐Dicyclopenta[a,b]naphthalenes

“…Homogenous gold catalysis has established itself in recent years as ap owerful tool in organic synthesis for the rapid generation of molecular complexity in as ingle step. [1][2][3][4][5][6][7][8][9][10][11] One of the main reasonsf or this has been the exceptional ability of salts and complexes of the Group 11 metal to selectively and efficiently activate p-rich acyclic compounds under mild conditions. Ap rominente xample of this mode of reactivity is the gold-catalyzed rearrangement of propargyl esters.…”

“…Ap rominente xample of this mode of reactivity is the gold-catalyzed rearrangement of propargyl esters. [2][3][4][5][6] These compounds have been shown to undergoe ither a1 ,2-or 1,3acyloxy shift to generate the corresponding gold-carbenoid or -allenic complex, both of which are able to further react to form ad iverse range of synthetically useful compounds. [2][3][4] Included in this has been efforts exploring the cycloisomerization chemistry of putative carbenoid (I)a nd cyclopentenium (II)a dducts of gold from [2,3]-or [3,3]-sigmatropicr earrangement/ Nazarovc yclization of 1,3-and 1,4-enyne esters by the transition-metal complex (Scheme 1).…”

“…[2][3][4][5][6] These compounds have been shown to undergoe ither a1 ,2-or 1,3acyloxy shift to generate the corresponding gold-carbenoid or -allenic complex, both of which are able to further react to form ad iverse range of synthetically useful compounds. [2][3][4] Included in this has been efforts exploring the cycloisomerization chemistry of putative carbenoid (I)a nd cyclopentenium (II)a dducts of gold from [2,3]-or [3,3]-sigmatropicr earrangement/ Nazarovc yclization of 1,3-and 1,4-enyne esters by the transition-metal complex (Scheme 1). [5][6][7][8][9]12] For instance, we and others recently reported efficient and convenient synthetic routes to 3a,6-methanoisoindole, bridged hex-andh eptenone, and cyclopropa[c]pentalene derivatives from gold(I)-catalyzed rearrangement of the correspondingp ropargyl esters.…”