Gold-catalyzed propargylic substitutions: Scope and synthetic developments

Abstract

SummaryThis personal account summarizes our recent developments in gold-catalyzed direct substitutions on propargylic (allylic, benzylic) alcohols, with various nucleophiles (and bi-nucleophiles) based on the σ- and/or π-acidity of gold(III) complexes. Synthetic developments are also briefly described.

Scope and advances in the catalytic propargylic substitution reaction

“…211 Gold stands out among the other conventional Lewis acids since it possesses a unique hard/so Lewis acid nature which allows the simultaneous activation of both alcohols and p-bonds that could possibly take the advantage to perform new domino processes, Scheme 173. 212 Campagne and co-workers described an excellent methodology for the gold-catalyzed allylation of propargylic alcohols 39 at room temperature, Scheme 174 213 The reaction was found to furnish products in moderate to good yield in the range of 30-68% with several catalysts like AuBr 3 , AuCl 3 , HAuCl 4 $3H 2 O, and AuCl. Whereas no product formation was observed with Ph 3 PAuCl, PdCl 2 (PhCN) 2 , PtCl 2 .…”

Efficient Thiolation of Alcohols Catalyzed by Long Chained Acid‐Functionalized Ionic Liquids under Mild Conditions

“…With the development of Green Chemistry, easily available and cheap alcohols are attractive sources of electrophiles and the only by‐product formed in the reaction of alcohols and thiols is water. Thus, direct nucleophilic substitution reactions of alcohols have gained much attention . Previously, we realized direct synthesis of polysubstituted olefins via construction of C‐C bonds from alcohols or alkenes with alcohols and also developed system for direct amination of alcohols , .…”

“…Thus, direct nucleophilic substitution reactions of alcohols have gained much attention. [18][19][20][21][22] Previously, we realized direct synthesis of polysubstituted olefins via construction of C-C bonds from alcohols or alkenes with alcohols and also developed system for direct amination of alcohols. [23,24] Generally, carbocations from alcohols were proposed as the active intermediates during the systems.…”

Mutual Cooperation in the Formal Allyl Alcohol Nucleophilic Substitution and Hydration of Alkynes for the Construction of γ‐Substituted Ketones

“…Based on this, we proposed a possible mechanism for this cascade reaction (Scheme ). The initial 5‐ endo‐dig cyclization through the hydroxyl group O−H insertion into the carbon–carbon triple bond activated by Au provided the dihydrofuran metal intermediate TS‐1 , which can be tautomerized to TS‐2 , followed by intermolecular hydroalkoxylation to give the five‐membered acetal product Int‐6 a . With the assistance of Lewis acid Au I or Au III salt, the C−O bond at the allylic position is cleaved, and simultaneously the ring‐opening of Int‐6 a occurred and gave the allyl cation intermediate TS‐4 .…”