Formation of Macrocycles by Catalytic Intramolecular Aromatic Cycloaddition of Metal Carbenes to Remote Arenes

Catalytic Intramolecular Addition of Metal Carbenes to Remote Furans

“…Their absence is consistent with results from intermolecular reactions with diazo ketones . Although these results were not optimized, they demonstrate, as did comparable aromatic cycloaddition reactions, inherent selectivity differences between diazoacetates and diazo ketones.…”

“…We have used the benzenedimethanol tether to link the diazocarbonyl carbene source to the reacting functional group, − and we did so this time. The synthesis of these compounds involved leaving group displacement on the monoprotected benzenedimethyl mesylate by the sodium salt of furfuryl alcohol and subsequent preparation of the diazocarbonyl compound, withthese steps occuring in moderate to high yield.…”

Gold‐Catalyzed Oxidative Alkyne Functionalization by N−O/S−O/C−O Bond Oxidants

“…[93] Interestingly under the typical catalytic condition, probable the oxidatively generated α-oxo gold carbene 103 experiences cyclopropanation with arene overcoming the traditional Friedel-Craft type arylation. This type of cyclopropanation has been reported [94,95,96] earlier with Rhcatalysts and diazo ketones/esters instead of alkynes whereas Zhang and coworkers successfully explored terminal alkynes for such kinds of transformation. In presence of a gold catalyst and external oxidant initially generated α-oxo gold carbene 103 converted to norcaradiene intermediate 104 and subsequent reversible electrocyclic ring-opening afforded tetrahydropyranone-fused cycloheptatriene 105 as a Buchner reaction product, which again isomerized to stable conjugated enone 106.…”

Macrocycle Formation from Catalytic Metal Carbene Transformations

“…23,24 Exclusive addition to the 3,4-position of the 4-methoxybenzyl derivative of 14 occurs in reactions catalyzed by Rh 2 (OAc) 4 , but the more reactive Rh 2 (pfb) 4 also produces the product from addition to the 1,2-position as a minor constituent of the reaction mixture (13:87). With 15, which upon diazo decomposition can undergo either addition to the carbon-carbon triple bond or addition to the aromatic ring, aromatic cycloaddition occurs exclusively when Rh 2 (MEOX) 4 The extent to which this macrocyclization process can be used for the preparation of large-ring esters can be seen in results from diazo decomposition of the diazoacetate 16 derived from triethylene glycol (Scheme 11).…”