Synthetic approaches to butenolides

A Synthetic Route to α‐Substituted Butenolides: Enantioselective Synthesis of (+)‐Ancepsenolide

“…Reduction Procedure using Pd(OAc) 2 /dppp/(TES)H or Pd(OAc) 2 / dppp/(TMS) 3 SiH or Pd(OAc) 2 /dppp/PMHS as Reductive Agent (Method B): To a solution of 4 (1 equiv. ), Pd(OAc) 2 (0.05 equiv.…”

“…Reduction Procedure Using Pd 2 (dba) 3 /PPh 3 /Bu 3 SnH as Reductive Agent (Method A): A suspension of Pd 2 (dba) 3 (0.01 mmol) and PPh 3 (0.1 mmol) in THF (4 mL) was stirred at room temperature (green color). After 5 min, a solution of compound 4 (0.7 mmol) in THF (3 mL) was added followed by Bu 3 SnH (1.4 mmol) (brown color).…”

“…[1a] Given their prevalence in nature and as synthetic intermediates, many methods have been developed for their de novo preparation [3] from both acyclic and oxacyclic precursors.…”

Synthesis of 3‐Fluorofuran‐2(5H)‐ones Based on Z/E Photoisomerisation and Cyclisation of 2‐Fluoro‐4‐hydroxybut‐2‐enoates

“…As an example, angelicalactone [8a,8b] has been utilised as a simple chiral butenolide precursor for the preparation of (+)-himbacine, [8c] known to be a significant inhibitor of M 2 receptors. The presence of several alkyl and aryl groups in one structure is also an essential feature of terpenoides that exhibit antifungal activity, [10] such as mintlactone [9] and derivatives of (-)-incrustoporine, or powerful pharmacophores, for example, in antitumour drugs Tamoxiphen and Droloxifene or in coronary vasodilator Amotriphene.…”

Copper/Iron‐Cocatalyzed Highly Selective Tandem Reactions: Efficient Approaches to Z‐γ‐Alkylidene Lactones

“…tones g-Alkylidene lactones have attracted considerable attention due to their diverse biological activities and ubiquitous structural units in natural products, [1,2] such as atranone [2a] and growth regulating reagent. [2b] In the past several decades, transition metal-catalyzed intramolecular hydroacyloxylation reactions of acetylenic acids have been demonstrated to construct this unique structural unit (Scheme 1).…”