Katalysierte Tandemreaktion aus Cyclisierung und Pinakol‐Umlagerung von 3‐Silyloxy‐1,5‐eninen

Abstract

Unter silberfreien Bedingungen wurden einfache 3‐Silyloxy‐1,5‐enine durch die Gold(I)‐katalysierte Titelreaktion in komplexe Cyclopentenderivate überführt. Für den abschließenden Demetallierungsschritt wurden 2‐Propanol und N‐Iodsuccinimid (NIS) effizient eingesetzt, sodass sowohl Diversität als auch Komplexität rasch erzielt werden können.

A Critical Comparison: Copper, Silver, and Gold

“…27 From the cationic intermediate, elimination to the biaryl product can be observed in addition to the aldehyde. 27 From the cationic intermediate, elimination to the biaryl product can be observed in addition to the aldehyde.…”

Gold‐Catalyzed Synthesis of Iodofulvenes

“…This clearly demonstrates that a direct rather than a stepwise exchange must take place, and that no "naked I + " is present. [9] This was confirmed by stoichiometric experiments, which were monitored by 1 H NMR under the (initial) reaction conditions but in the absence of any cationic gold catalyst (Scheme 4). The formation of the corresponding gold acetylide 5 and iodobenzene 4 was monitored.…”

Platinum‐Catalyzed Cyclization/[1,2]‐Alkyl Migration/Allyl Shift/Cyclization Cascade of Epoxy Alkynyl Allyl Ethers: A Step‐Economical Route to Spirobenzo[h]chromanones

“…55 [e] [a] The reaction was conducted by using 1 a (0.1 mmol), catalyst (5-10 mol %), 5 MS (50 mg) in solvent (3 mL When the R 2 group was an aliphatic group, the allyl-shift products 4 were obtained in the presence of 5 mol % PtI 4 . Addition of FeA C H T U N G T R E N N U N G (acac) 3 , 5 MS and oxygen did not improve the result. With the growth of chain length, the yields increased from 35 to 68 % (Scheme 3, products 4 a and 4 b).…”

“…. Thus the use of 5 mol % PtI 4 and 2.5 mol % FeA C H T U N G T R E N N U N G (acac) 3 with 5 MS in dry anisole at 120 8C under an oxygen atmosphere were considered as the optimal reaction conditions. Encouraged by these results, and aiming to obtain a variety of spirobenzo[h]chromanones, we next examined the scope of this catalytic process.…”