Enantioselective construction of spiro-tetrahydroquinoline scaffolds through asymmetric catalytic cascade reactions

摘要

An efficient and concise strategy has been successfully developed for merging spiro-tetrahydroquinoline with spiro-benzofuranone into a single new skeleton through asymmetric catalytic cascade reactions catalyzed by quinine-derived chiral bifunctional squaramide organocatalysts. In this approach, differently substituted spiro-tetrahydroquinoline derivatives were smoothly obtained with high yields, and excellent diastereoselectivities and enantioselectivities (up to 99 yield, up to >20 : 1 dr, up to >99 ee, 40 examples) under mild reaction conditions.