Construction of Chiral Spiro-Bridged Rings with Four Consecutive Stereocenters via Dearomative Diels–Alder Reactions of Anthracenes

A highly diastereo- and enantioselective dearomative Diels-Alder reaction was accomplished by chiral <i>N</i>,<i>N</i>'-dioxide/Mg(II) complex catalyst. Various anthracene derivatives and methyleneindolinones efficiently transformed into the corresponding chiral spiro-bridged cyclic products with four consecutive stereocenters in good yields, excellent dr and er values under mild conditions (46 examples, up to 99% yield, >19:1 dr, >99:1 er). Gram-scale synthesis of chiral products and their further transformations were feasible. On the basis of theoretical calculation, possible working modes were provided to understand the origin of stereoselectivity of this transformation.