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. 2023 Apr 16;28(8):3513. doi: 10.3390/molecules28083513

Table 2.

LS-Sc3+ promoted the Michael addition/dehydration tandem reaction between 3-acetyl-2-hydroxy-2-methylchromenes and indoles [33] 1.

graphic file with name molecules-28-03513-i001.jpg
Entry Catalyst R1 R2 R3 R4 R5 Yield (%) 2
1 LSA-Sc3+ Br H H H H 93 (90)
2 LSA-Sc3+ Br H H H Me 98
3 LSA-Sc3+ Br H H OMe H 97
4 LSA-Sc3+ Br H H Br H 61
5 LSA-Sc3+ Br H Me H H 93
6 LSA-Sc3+ Br H H H Ph 85 3
7 LSA-Sc3+ Cl H H H H 96
8 LSA-Sc3+ Cl H H H Me 96
9 LSA-Sc3+ H H H H H 93
10 LSA-Sc3+ OMe H H H H 86
11 LSA-Sc3+ tBu H H H H 96
12 LSA-Sc3+ H Me H H H 68
13 LSA-Sc3+ H OMe H H H 61
14 LSA-Sc3+ Me Me H H H 83
15 SiO2-Sc3+ Br H H H H 92 (50)
16 resin-Sc3+ Br H H H H 87 (63)

1 Reaction conditions: 3-acetyl-2-hydroxy-2-methylchromene derivative (0.5 mmol), indole derivative (0.6 mmol), LSA-Sc3+ (1.2 mol%), EtOH (1 mL), 80 °C, 8 h. Isolated yields. The yield in parentheses shows the reuse of the catalyst in the third run. 2 Isolated yield. 3 Catalyst amount = 2 mol%. 1-Methyl-2-phenyl-1H-indole was used as the Michael donor.