Figures (13)  Tables (6)

    • Figure 1. 

      Natural medicinal and agricultural products of furan derivatives.

    • Figure 2. 

      Regioselective gold-catalyzed isomerization of 1 to 2 or 3.

    • Figure 1. 

      Proposed creation of furans from alkynyl epoxides.

    • Figure 3. 

      Optimization of R2 = Ph and p-BrPh substitutes S2/AuCl3 complexes.

    • Figure 4. 

      R2 = Ph derived furan formation in acetonitrile.

    • Figure 5. 

      R2 = p-BrPh derived furan formation in acetonitrile.

    • Figure 6. 

      R2 = Ph and R1 = CH2CH2OH derived furan formation using various functionals in acetonitrile.

    • Figure 7. 

      R2 = Ph and R1 = CH2CH2OH substituted furan formation profile in various solvents.

    • Figure 8. 

      Furan formation profile using various solvation models.

    • Figure 9. 

      Energy profiles of the mechanism in various basis sets.

    • Figure 2. 

      Proposed gold-catalyzed mechanism to obtain oxetene from alkynyl epoxides.

    • Figure 10. 

      Optimization of S3/AuCl3 complex in acetonitrile.

    • Figure 11. 

      The formation of oxetene (R2 = H) in acetonitrile.

    • R2 TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      Ph 15.5 −0.1 2.6 −63.3 −1.1 −41.3 −6.4 −55.1 −34.5 −71.6
      p−BrPh 14.8 0.6 2.4 −65.9 −1.9 −42.5 −9.6 −59.4 −38.1 −71.9

      Table 1. 

      Energies of reaction (in kcal/mol), (R1 = (CH2)2OH), with the M06-2X functional in acetonitrile.

    • Method TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      B3LYP 12.5 0.6 1.6 −56.0 0.7 −31.5 2.8 −46.2 −26.5 −63.1

      Table 2. 

      Energies (in kcal/mol) with R2 = Ph and R1 = CH2CH2OH using B3LYP functional.

    • Solvent ε TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      Acetonitrile 37.5 15.5 −0.1 2.6 −63.3 −1.1 −41.3 −6.4 −55.1 −34.5 −71.6
      Methanol 32.7 15.6 0.3 2.7 −63.3 −1.1 −41.2 −6.3 −55.0 −34.0 −71.0
      Acetone 20.7 15.5 1.0 3.0 −62.8 −1.3 −39.6 −5.8 −54.5 −33.9 −70.9
      Dichloromethane 8.9 18.6 4.8 6.2 −60.3 1.7 −27.0 3.5 −49.4 −29.5 −69.1
      Gas phase 0 22.0 8.7 25.6 −71.7 −0.4 −25.2 0.4 −50.3 −25.1 −70.7

      Table 3. 

      Energies of reaction steps (in kcal/mol) with R2 = Ph and R1 = CH2CH2OH substituents in various solvents.

    • Solvation model TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      PCM 15.5 −0.1 2.6 −63.3 −1.1 −41.3 −6.4 −55.1 −34.5 −71.6
      C-PCM 16.0 3.3 2.7 −62.6 −0.6 −40.6 −6.1 −54.7 −34.4 −72.5
      SMD 11.3 −2.2 −0.1 −64.4 −2.0 −44.5 −11.2 −62.1 −40.5 −75.0

      Table 4. 

      Energies of reaction steps (in kcal/mol) (R2 = Ph and R1 = CH2CH2OH) in acetonitrile and various solvation models.

    • Basis set TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      6-31+g(d) 15.5 −0.1 2.6 −63.3 −1.1 −41.3 −6.4 −55.1 −34.5 −71.6
      6-31+g(d,p) 15.2 0.7 2.4 −63.2 −3.9 −43.9 −8.9 −55.4 −35.8 −71.3
      6-311+g(d,p) 17.5 2.0 4.0 −59.8 −0.7 −40.9 −5.8 −52.2 −32.7 −68.3
      6-31g(d) 14.9 −0.6 0.6 −66.3 −2.4 −41.8 −7.7 −56.3 −35.9 −74.2

      Table 5. 

      Energies of reaction steps (in kcal/mol) using various basis sets in acetonitrile.

    • Basis set Job CPU time
      TS1 S2 TS2 S3 TS3 S4 TS4 S5 TS5 2a
      6-31+g(d) 0 d 23 h
      38 min 40.8 s      		 1 d 3 h
      55 min 22.9 s      		 1 d 3 h
      28 min 33.5 s      		 1 d 4 h
      0 min 53.6 s      		 1 d 6 h
      12 min 33.0 s      		 1 d 8 h
      7 min 2.3 s      		 0 d 14 h
      36 min 50.0 s      		 0 d 16 h
      58 min 7.2 s      		 0 d 16 h
      34 min 4.6 s      		 0 d 15 h
      54 min 57.4 s
      6-31+g(d,p) 1 d 6 h
      6 min 9.9 s      		 1 d 12 h
      5 min 10.6 s      		 1 d 13 h
      50 min 18.4 s      		 1 d 10 h
      23 min 31.2 s      		 1 d 14 h
      7 min 27.6 s      		 1 d 13 h
      45 min 27.4 s      		 1 d 1 h
      46 min 46.4 s      		 0 d 17 h
      17 min 24.7 s      		 0 d 18 h
      51 min 57.7 s      		 0 d 18 h
      33 min 27.2 s
      6-311+g(d,p) 1 d 0 h
      48 min 59.0 s      		 1 d 2 h
      3 min 56.9 s      		 1 d 2 h
      37 min 44.5 s      		 1 d 5 h
      23 min 41.2 s      		 1 d 2 h
      46 min 16.9 s      		 1 d 5 h
      12 min 7.6 s      		 1 d 6 h
      10 min 27.9 s      		 1 d 5 h
      27 min 23.0 s      		 1 d 8 h
      10 min 44.4 s      		 1 d 2 h
      55 min 8.0 s
      6-31g(d) 0 d 3 h
      12 min 54.9 s      		 0 d 3 h
      12 min 50.8 s      		 0 d 3 h
      17 min 53.9 s      		 0 d 3 h
      22 min 20.4 s      		 0 d 3 h
      18 min 26.8 s      		 0 d 3 h
      13 min 54.5 s      		 0 d 3 h
      18 min 24.1 s      		 0 d 3 h
      23 min 56.9 s      		 0 d 3 h
      26 min 13.0 s      		 0 d 3 h
      22 min 26.0 s

      Table 6. 

      The computational cost (CPU time) for each basis set.