Optimization of reaction conditionsa,b.
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Entry | Deviation from the standard conditions | Yieldc,d [%] |
1 | None | 75 |
2 | 5% aq. xylene/120 °C instead of H2O/100 °C | 56e |
3 | CH3CN/80 °C instead of H2O/100 °C | 21 |
4 | THF/70 °C instead of H2O/100 °C | 32 |
5 | 1,4-Dioxane/100 °C instead of H2O/100 °C | 25 |
6 | t-BuOH/85 °C instead of H2O/100 °C | 31 |
7 | 80 °C instead of 100 °C | 48 |
8 | Rh(COD)2OTf/xylene instead of [Rh(COD)CI]2 catalyst/H2O | 16 |
9 | Rh(COD)2SbF6/xylene instead of [Rh(COD)CI]2 catalyst/H2O | 25 |
10 | [Ir(COD)CI]2/xylene instead of [Rh(COD)CI]2 catalyst/H2O | 21 |
11 | [Ru(p-cymene)CI2]2/xylene instead of [Rh(COD)CI]2 catalyst/H2O | 12 |
Reaction conditions: 1a (0.3 mmol) and catalyst (5 mol%) in 3 mL of solvent under an inert atmosphere.
All commercial solvents used in the reaction.
Isolated yields of exo-2a.
Observed exclusive exo-selectivity.
46% yield observed in the presence of commercial xylene.