S. No. | Entry | R1 | R2 | R3 | R4 | R5 | R6 | 9 Yield (%)a | |
1 | a | H | OH | H | H | H | H | 88 | |
2 | b | H | OH | H | OCH3 | H | H | 89 | |
3 | c | H | OH | H | H | OCH3 | H | 90 | |
4 | d | H | OH | H | H | OH | H | 88 | |
5 | e | H | OH | OCH3 | H | OCH3 | H | 89 | |
6 | f | OH | OH | H | H | H | H | 75, 89b | |
7 | g | OH | OH | H | OCH3 | H | H | 70, 85b | |
8 | h | OH | OH | H | H | OCH3 | H | 75, 90b | |