A three-component reaction for rapid access to underexplored 1,3-thiazine-2-thionesElectronic supplementary information (ESI) available: Experimental procedures and analysis data for all isolated new compounds as well as crystal structures of compounds 2a and 6b. CCDC 1049355 and 1049334. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c5ob00377f

Driven by the shortage of known effective possibilities for the synthesis of 4-hydroxy-3,4-dihydro-2 H -1,3-thiazine-2-thiones on the one hand and the promising potential of these structures as novel drug candidates on the other hand, synthetic access to 4-hydroxy-3,4-dihydro-2 H -1,3-thiazine-2-thiones was developed. The desired products could be synthesized effectively and facilely starting from β-chlorovinyl aldehydes with the aid of a new MCR (multicomponent reaction). Furthermore, the 4-hydroxy-3,4-dihydro-2 H -1,3-thiazine-2-thiones are shown to be appropriate substrates in the preparation of diverse annulated polycyclic systems. A newly developed multicomponent reaction opens access to a variety of (poly)heterocyclic structures containing the underexplored skeleton of 1,3-thiazine-2-thione.