Table 2 Scope of the gold-catalysed σ-type CPC transfer to terminal alkynes

From: Accessing elusive σ-type cyclopropenium cation equivalents through redox gold catalysis

  1. Reaction conditions: CpBX 1 (0.2 mmol, 1.0 equiv.), terminal alkyne 2 (0.2 mmol, 1.0 equiv.), (Me2S)AuCl (5 mol%) and L1 (10 mol%) were stirred in CH3CN (2.0 ml) at room temperature for the indicated time, unless noted otherwise. Isolated yields are given. Bz, benzoyl; Cbz, carbobenzyloxy; TBS, tert-butyldimethylsilyl.
  2. aAn acetylene balloon (1 atm) and L1 (25 mol%) were used at 40 °C.
  3. bCpBX 1k (0.4 mmol, 2.0 equiv.), diyne 2 (0.2 mmol, 1.0 equiv.), (Me2S)AuCl (10 mol%) and L1 (20 mol%) were used.
  4. cReactions carried out at 40 °C.
  5. d0.1 mmol scale.
  6. eCpBX 1j (1.5 equiv.) and L1 (25 mol%) were used instead.
  7. f(Me2S)AuCl (2 mol%) and L1 (4 mol%) were used instead.
  8. g2 mmol scale.
  9. h1.2 mmol scale.
  10. i0.6 mmol scale.
  11. j1.8 mmol scale.
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