Stereocontrol in Conformationally Stable C(sp 2 )─C(sp 3 ) Atropisomers

We report a two-step sequence for the enantioselective construction of a rare family of stable C(sp²)─C(sp³) atropisomers featuring two additional stereogenic centers. The process begins with an organocatalyzed dihydrobenzofurannulation that establishes and controls the stereochemistry of two carbon centers, followed by a highly diastereoselective functionalization that significantly enhances the barrier to diastereomerization of the C(sp²)─C(sp³) bond, effectively locking and stabilizing its configuration.