Total synthesis of (.+-.)-gnididione and (.+-.)-isognididione

Propynyllithium

“…Under these conditions, the TBS ether of propargyl alcohol, after lithiation, displaces the primary triflate, which is a particularly difficult substrate due to the β-oxygen functionality, in 10 min at −20 • C (eq 12). 19 The α-ethoxyethyl ether of propargyl alcohol, after lithiation in THF with n-BuLi, has been used in a double addition to a dione in an approach to [5] …”

“…2 Additions proceed under nonchelation-controlled conditions and are less stereoselective than the corresponding additions of Propynylmagnesium Bromide. 5 The linear nature of the reagent allows addition to hindered ketones to give the propargylic alcohols which can be transformed into allenyl sulfoxides with Benzenesulfenyl Chloride (eq 2). 6 Propynyllithium prepared from 1,2dibromopropane also reacts smoothly with aldehydes and ketones in high yield (eq 3).…”

2,3‐Dihydrofurans as Potential Cytotoxic and Antibacterial Agents: Tandem Knoevenagel−Michael Cyclization for the Synthesis of 2,3‐Dihydrofurans by Using α‐Tosyloxy Ketone Precursors

“…[11] [12] Recently, the beneficial applications of naturally occurring compounds such as flavones, chromones, coumarins, pyrans, benzofurans, and their synthetic hybrids against bacterial strains have gathered significant prominence because of their biocompatibility as well as lower toxicity. [13 -26] However, benzofurans, one of the vital members of these oxygen-containing heterocycles, [27][28][29][30][31] have been less explored for their antibacterial activity. Dihydrofurans are the most important heterocyclic compounds which show a wide range of biological activities.…”

Combined Claisen Rearrangement and Oxidative Cyclization as a Route to Hydroxymethyl Dihydrofuran‐Annulated Coumarins

“…Dihydrofurans are important heterocycles with widespread occurrence in nature. They are an integral part of many natural and synthetic constituents with wide range of biological activities .…”