Thiopyrans and their Benzo Derivatives

Enantioselective Organocatalytic Tandem Michael−Aldol Reactions: One-Pot Synthesis of Chiral Thiochromenes

“…Despite the fact that the chemistry of thiopyrans has been much less explored than that of the analogous pyrans, recently the interest in the sulfur-containing heterocycles has been significantly surged since a wide range of biological activities associated with the scaffold have been identified . For example, 1-benzothiopyrans exhibit anti-inflammatory, anti-bacteria, anti-hyperplasia, anti-psychiatric, analgesic, and anti-cancer activities.…”

“…Accordingly, the development of new and facile synthetic strategies to access such heterocycles is of considerable interest. Various methods for their preparation have been reported. , However, survey of the literature reveals that these approaches involve multistep sequences; moreover, to date, to the best of our knowledge, only two studies of the asymmetric version for synthesis of the scaffold have been described using either optically pure starting material or a chiral auxiliary …”

Triflic-Acid-Catalyzed Tandem Allylic Substitution–Cyclization Reaction of Alcohols with Thiophenols—Facile Access to Polysubstituted Thiochromans

“…3,4-Dihydro-2 H -1-benzothiopyrans (commonly known as thiochromans) are one of the least explored sulfur-based heterocycles in terms of synthetic methodologies. 1 This is indeed surprising because several thiochroman compounds, as well as their derivatives such as thiochromones, thiochromenes, and thiochroman-4-ones, have exhibited interesting biological activities. 2 However, the synthetic protocols available for accessing the core thiochroman motif remain relatively limited and usually entail the use of drastic conditions (Scheme 1).…”

Switching Selectivity of α-Enolic Dithioesters: One Pot Access to Functionalized 1,2- and 1,3-Dithioles

“…Among the various heterocyclic frameworks, heterocycles containing sulfur atom(s) are versatile privileged scaffolds present in many biologically active molecules and pharmaceuticals . 1,2-Dithiole derivatives show many significant pharmacological activities .…”