Catalytic Enantio‐ and Diastereoselective Formation of β‐Sultones: Ring‐Strained Precursors for Enantioenriched β‐Hydroxysulfonyl Derivatives

Sultones swing! Sulfenes, the highly reactive sulfonyl equivalents of ketenes, were used for the first time as substrates in asymmetric catalysis. A [2+2] cyclocondensation reaction catalyzed by a tertiary amine enabled the asymmetric synthesis of β-sultones, which are convenient precursors of β-hydroxysulfonyl derivatives (EWG: electron-withdrawing group; Tf: triflate, (DHQ)2PYR: dihydroquinine-2,5-diphenyl-4,6-pyrimidinediyl diether, Nu: nucleophile).