Answers are grounded in this paper and cite their sources.
Chiral phosphoric acid catalyzed enantioselective transfer hydrogenation of hydroxylactams has been realized to provide enantioenriched tetrahydro-β-carbolines in dioxane at room temperature (up to 94% yield, 90% ee).
No takes yet. Share an insight, caveat, or question.
Yin et al. (2013) studied this question.
Synapse has enriched 10 related papers. Consider them for comparative context: