S. No. | Entry | R1 | R2 | R3 | R4 | R5 | R6 | 10 Yield (%)a | |
1 | a | H | OH | H | H | H | H | 84 | |
2 | b | H | OH | H | H | OCH3 | H | 87 | |
3 | c | H | OH | H | H | OH | H | 89 | |
4 | d | H | OH | OCH3 | H | H | OCH3 | 88 | |
5 | e | OH | OH | H | H | OCH3 | H | 78, 88b | |
6 | f | OH | OH | OCH3 | H | H | OCH3 | 80, 85b | |