Tandem Platinum Dichloride Catalysis and Thermal Reaction of Enynes: Versatile Synthetic Platform Based on Bicyclo[4.1.0]hept‐2‐enes

Abstract

A tandem platinum dichloride-catalyzed cycloisomerization and rearrangement reaction of enynes leads to the formation of 2,4-pentadienals, 1-aryl-tetrahydro-1H-indenes, or 3-methylene-4-vinylcyclohex-1-enes; depending upon the substituent(s) and tether group of the enynes, the platinum dichloride-catalyzed cycloisomerization products, bicyclo-hept-2-enes, undergo a Claisen rearrangement, a 1,5-hydrogen shift, or a vinylcyclopropane rearrangement.

Defect‐Related Luminescence in ­Nitridoborate Nitride, Mg3Ga(BN2)N2

“…The potential of the HelPHOS–gold complexes in catalysis has been established further by studies on the cycloisomerization of the N‐tethered dienynes 16 (Scheme ). Under platinum catalysis, these substrates are known to produce bicyclo[4.1.0]heptenes, which may then undergo a thermal vinylcyclopropane–cyclopentene rearrangement 19. To the best of our knowledge, neither gold‐promoted nor enantioselective variants of these reactions have been reported so far.…”

Phosphathiahelicenes: Synthesis and Uses in Enantioselective Gold Catalysis

“…The promising enantioselectivity levels above encouraged us to extend our investigations to the cycloisomerization of different classes of enynes. At first, dienynes 13 17 were considered that display conjugated enyne moieties (Scheme ). Depending on the nature of the R substituent, the gold‐catalyzed cycloisomerization affords either the aza‐bicyclo[4.1.0]heptene 15 (for R=H) or the tricyclic derivative 14 (for R=Ph), which results from a vinylcyclopropane‐cyclopentene rearrangement18 of the intermediate aza‐bicyclo[4.1.0]heptene.…”

Helicenes with Embedded Phosphole Units in Enantioselective Gold Catalysis

“…Under platinum catalysis, these substrates are known to produce bicyclo[4.1.0]heptenes, which may then undergo a thermal vinylcyclopropane-cyclopentene rearrangement. [19] To the best of our knowledge, neither gold-promoted nor enantioselective variants of these reactions have been reported so far. We observed that these reactions take place at room temperature in the presence of the chiral gold complexes (S P ,P)-9 a'-endo and (S P ,P)-12 a'-endo, under even milder conditions than with platinum catalysis.…”