Rational Design of a Gold Carbene Precursor Complex for a Catalytic Cyclopropanation Reaction

Abstract

Bridging gas- and solution-phase chemistry: A gold(I) carbene precursor complex has been developed and investigated for catalytic cyclopropanation. Formation of the carbene intermediate was first probed by mass spectrometry, followed by cyclopropanation of p-methoxystyrene in solution. The imidazolylidene leaving group serves as a base generated in situ that is necessary in the putative catalytic cycle.

Quantitative Description of Structural Effects on the Stability of Gold(I) Carbenes

“…In the proposed cycle (Scheme ), the gold carbene cyclopropanates p ‐methoxystyrene, and the SO 2 imidazolylidene moiety further dissociates to give SO 2 and imidazolylidene 12 16. The latter acts as an in situ‐formed base within the cycle and deprotonates another molecule of 10 a , which undergoes auration to restore gold complex 1 1a. This result is the starting point for the present study.…”

Gold(I) Carbenes by Retro-Buchner Reaction: Generation and Fate

“…15,16 The gold(I)-catalyzed retro-Buchner reaction obviates the use of diazo derivatives to generate reactive gold(I) carbenes. Indeed, some diazo compounds are shock-sensitive.…”

Gold Sulfonium Benzylide Complexes Undergo Efficient Benzylidene Transfer to Alkenes

“…[5][6][7][8][9][10] However,o ur understanding of the mechanisms of gold(I) to alkene carbene transfer is largely restricted to information gleaned from indirect experimental observations, such as the product ratios and stereoselectivity of catalytic reactions, [14,15] from gas-phase reactions, [16][17][18][19] and from computational analyses. [4,[14][15][16][17][18][19] Largelya bsentf rom the discussion of the mechanisms of gold to alkene carbenet ransfer are the potentiali nsights gained from analysiso fc arbene transferf rom well-defined carbene complexes in the condensed phase. [4,[14][15][16][17][18][19] Largelya bsentf rom the discussion of the mechanisms of gold to alkene carbenet ransfer are the potentiali nsights gained from analysiso fc arbene transferf rom well-defined carbene complexes in the condensed phase.…”

“…[20][21][22] However,e xtracting detailed mechanistic information relevant to catalysis from these stoichiometric carbene transfer processes is complicated by the (1) excessive stabilization of the carbene complex, (2) in situ generation of the carbene complex with strong Lewis acids underc ryogenic conditions, and/or( 3) the extreme facility of carbene transfer. [18,25,26] However carbene transferf rom F requiresf orcingc onditions and as tabilizing C1 anisyl group for spontaneous activation and undergoes irreversible carbene formation, all of whichw ould complicate kinetic andm echanistic analysiso fc arbene transfer. [18,25,26] However carbene transferf rom F requiresf orcingc onditions and as tabilizing C1 anisyl group for spontaneous activation and undergoes irreversible carbene formation, all of whichw ould complicate kinetic andm echanistic analysiso fc arbene transfer.…”