Gold(I) Carbenes by Retro-Buchner Reaction: Generation and Fate
نویسندگان
چکیده
The fate of the aryl gold(I) carbenes generated by retro-Buchner reaction of ortho-substituted 7-aryl-1,3,5-cycloheptatrienes is dependent on the constitution of the ortho substituent. Indenes and fluorenes are obtained by intramolecular reaction of highly electrophilic gold(I) carbenes with alkenes and arenes. According to density functional theory calculations, the gold-catalyzed retro-Buchner process occurs stepwise, although the two carbon-carbon cleavages occur on a rather flat potential energy surface.
منابع مشابه
Stereoselective cis-Vinylcyclopropanation via a Gold(I)-Catalyzed Retro-Buchner Reaction under Mild Conditions
A highly stereoselective gold(I)-catalyzed cis-vinylcyclopropanation of alkenes has been developed. Allylic gold carbenes, generated via a retro-Buchner reaction of 7-alkenyl-1,3,5-cycloheptatrienes, react with alkenes to form vinylcyclopropanes. The gold(I)-catalyzed retro-Buchner reaction of these substrates proceeds by simple heating at a temperature much lower than that required for the rea...
متن کاملGold(I)‐Catalyzed Synthesis of Indenes and Cyclopentadienes: Access to (±)‐Laurokamurene B and the Skeletons of the Cycloaurenones and Dysiherbols
The formal (3+2) cycloaddition between terminal allenes and aryl or styryl gold(I) carbenes generated by a retro-Buchner reaction of 7-substituted 1,3,5-cycloheptatrienes led to indenes and cyclopentadienes, respectively. These cycloaddition processes have been applied to the construction of the carbon skeleton of the cycloaurenones and the dysiherbols as well as to the total synthesis of (±)-l...
متن کاملCyclobutene vs 1,3-Diene Formation in the Gold-Catalyzed Reaction of Alkynes with Alkenes: The Complete Mechanistic Picture
The intermolecular gold(I)-catalyzed reaction between arylalkynes and alkenes leads to cyclobutenes by a [2 + 2] cycloaddition, which takes place stepwise, first by formation of cyclopropyl gold(I) carbenes, followed by a ring expansion. However, 1,3-butadienes are also formed in the case of ortho-substituted arylalkynes by a metathesis-type process. The corresponding reaction of alkenes with a...
متن کاملGold(I) Carbenoids: On‐Demand Access to Gold(I) Carbenes in Solution
Chloromethylgold(I) complexes of phosphine, phosphite, and N-heterocyclic carbene ligands are easily synthesized by reaction of trimethylsilyldiazomethane with the corresponding gold chloride precursors. Activation of these gold(I) carbenoids with a variety of chloride scavengers promotes reactivity typical of metallocarbenes in solution, namely homocoupling to ethylene, olefin cyclopropanation...
متن کاملA Non-Diazo Approach to α-Oxo Gold Carbenes via Gold-Catalyzed Alkyne Oxidation
For the past dozen years, homogeneous gold catalysis has evolved from a little known topic in organic synthesis to a fully blown research field of significant importance to synthetic practitioners, due to its novel reactivities and reaction modes. Cationic gold(I) complexes are powerful soft Lewis acids that can activate alkynes and allenes toward efficient attack by nucleophiles, leading to th...
متن کامل