Catalytic Asymmetric Synthesis of Axially and Centrally Chiral 1,2-Dihydrobenzofuro3,2-bpyridines through a 2 + 2 Cycloaddition/Retroelectrocyclization/Re-Cycloaddition Cascade

]pyridines containing both axially and centrally chiral elements in high yields and excellent stereoselectivities (up to >99% yield, 91:9 dr, 98% ee). A control experiment revealed that this process proceeded through a multistep 2 + 2 cycloaddition/retroelectrocyclization/tautomerism/1,6-conjugate addition cascade.