Two different enantioselective organocatalytic cascade reactions to form new sulfur‐containing spirocyclic scaffolds are described. In the first approach, benzothiophen‐2‐one and enals react in the presence of a secondary amine catalyst through a Michael/Michael/Aldol sequence to afford the final spiro‐cyclohexene carbaldehydes in good yields (up to 68 %) and with excellent selectivities [20:1 diastereomeric ratio (dr), up to 99 % ee]. In the second approach, the double Michael addition of benzothiophen‐2‐one to aromatic dienones with primary amine catalysis produces the corresponding spiro‐cyclohexanones in good yields (up to 76 %) and with moderate‐to‐high selectivities (up to 12:1 dr, up to 90 % ee). Moreover, the use of N‐phenylrhodanine as the bis‐nucleophile for these reactions also allowed the formation of the corresponding spirocyclic adducts.

A novel and efficient synthesis of enantiomerically pure α‐dibenzylamino α′‐sulfinyl ketones starting from a mixture of both epimers of α‐bromo α′‐(R)‐sulfinyl ketone has been realized through combined in situ substitution–epimerization in a so‐called Dynamic Kinetic Resolution (DKR). The scope of the reaction has been examined, and four differently substituted α‐(S)‐dibenzylamino α′‐(R)‐sulfinyl ketones were obtained in good yields with excellent diastereoselectivities. The utility of these derivatives was further illustrated with a highly stereoselective synthesis of syn‐(2R,1′S)‐2‐(1‐dibenzylaminoalkyl)oxiranes.

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Crystallization-Induced Diastereomer Transformation (CIDT) of α-bromo-α′-(R)-sulfinylketones is reported. This process provides not readily accessible enantiopure stereolabile αbromoketones, which after diastereoselective carbonyl group reduction lead to the corresponding highly value-added anti and syn-bromohydrins with excellent diastereoselectivities. As an application, a diastereodivergent synthesis of enantiopure hemlock alkaloid (+)-α-conhydrine and its diastereomer (−)-β-conhydrine is also described.