New developments in gold-catalyzed manipulation of inactivated alkenes

Abstract

SummaryOver the recent years, the nucleophilic manipulation of inactivated carbon–carbon double bonds has gained remarkable credit in the chemical community. As a matter of fact, despite lower reactivity with respect to alkynyl and allenyl counterparts, chemical functionalization of isolated alkenes, via carbon- as well as hetero atom-based nucleophiles, would provide direct access to theoretically unlimited added value of molecular motifs. In this context, homogenous [Au(I)] and [Au(III)] catalysis continues to inspire developments within organic synthesis, providing reliable responses to this interrogative, by combining crucial aspects such as chemical selectivity/efficiency with mild reaction parameters. This review intends to summarize the recent progresses in the field, with particular emphasis on mechanistic details.

Dimeric TADDOL Phosphoramidites in Asymmetric Catalysis: Domino Deracemization and Cyclopropanation of Sulfonium Ylides

“…[10] We believe that the substrate isomers must interconvert at arate higher than that of the cyclopropanation reaction. Ther acemization of chiral racemic starting materials such as rac-3a is ensured by their dynamic conversion into the achiral, linear allylic isomers (cf.…”

“…[8] Recently,o ur group described ag old(I)-catalyzed intramolecular cyclopropanation of unactivated olefins with sulfonium ylides that proceeds through alkene activation. [9,10] Herein, we report an enantioselective intramolecular cyclopropanation of allylic esters through as ynergistic effect in abimetallic,dimeric catalyst framework. [11] In this process,an unusual and highly efficient deracemization takes place, whereby the same catalyst engages in two distinct, cooperative catalytic cycles and which results in ad omino catalytic asymmetric transformation (Scheme 1).…”

Small-molecule activation at Au(iii): metallacycle construction from ethylene, water, and acetonitrile

“…1 Gold is known for its ability to π-coordinate and thereby activate alkenes and alkynes towards nucleophilic attack, which is considered to be a key step in gold catalysis. 1 Gold is known for its ability to π-coordinate and thereby activate alkenes and alkynes towards nucleophilic attack, which is considered to be a key step in gold catalysis.…”

Gold‐Catalyzed Dearomatization of 2‐Naphthols with Alkynes

“…Contrarily,t he use of eco-friendly,r eadily available and cheap unactivated unsaturated hydrocarbons in the site-specific dearomatization of naphthols derivatives faced far less success. [9] This cascade sequence exploits the intrinsic attitudeo f[ Au I ] species in performing specific electrophilic activation of alkynes [10] and allenes [11] towards nucleophilic additions, enabling dearomatization of the naphthyl core and construction of elaborated side-chains in one pot (Scheme 1). [9] This cascade sequence exploits the intrinsic attitudeo f[ Au I ] species in performing specific electrophilic activation of alkynes [10] and allenes [11] towards nucleophilic additions, enabling dearomatization of the naphthyl core and construction of elaborated side-chains in one pot (Scheme 1).…”

“…[5] In conjunction with our interests on the catalytic manipulation of arenesa nd heteroarenes, [6,7] we present here an unprecedented gold-catalyzed dearomatization protocol of 2-naphthyl alkynols based on ac ascade reaction sequence comprising a [ 3,3]-propargylic Claisen rearrangement [8] and subsequent nucleophilic trapping of the resulting allenyl intermediate. [9] This cascade sequence exploits the intrinsic attitudeo f[ Au I ] species in performing specific electrophilic activation of alkynes [10] and allenes [11] towards nucleophilic additions, enabling dearomatization of the naphthyl core and construction of elaborated side-chains in one pot (Scheme 1). [12] To verify the reliability of our workingi dea, ap reliminary surveyo fr eaction parameters was carriedo ut with the readily availablen aphthylpropynol 1a.D elightfully,t reatment of 1a with PPh 3 AuCl/AgSbF 6 (2.5 mol %) in dry toluene provided the desired dearomatized naphthaleneone 2a in promising 28 % yield alongw ith ac omplex mixture of byproducts.…”