Asymmetric Desymmetrization of a σ-Symmetric Erythritol Derivative Using C2-Symmetric Bis-sulfoxide: a Total Synthesis of (+)-Aspicilin

Use of chiral auxiliaries in the asymmetric synthesis of biologically active compounds: A review

“…(+)‐Aspicilin was shown to have promising inhibitory activity against human cancer cell lines A549 (IC 50 = 14.7 μmol/L in 24 h), HeLa (IC 50 = 17.9 μmol/L in 24 h), and MCF7 (IC 50 = 12.0 μmol/L in 24 h) but no cytotoxic activity against Neuro2a or MDA‐MB‐231 cancer cells nor antibacterial or antifungal properties . Nevertheless, its 18‐membered macrocyclic ring containing three contiguous chiral centers has attracted the attention of synthetic chemists …”

The Chemistry of C2-Symmetric Bis(sulfoxides): A New Approach in Asymmetric Synthesis

“…Upon treatment with KHMDS, followed by acetylation, enol ethers 134a and 134b could be obtained in good yield and with a high diastereoselectivity (> 96%). This strategy has proved quite useful for the total synthesis of several relevant natural compounds such as (−)‐allosamizoline114 ( 135 ⇄ 137 ), (−)‐galaquercitol,115 (+)‐aspicillin,116 mosin B 117. Mechanistic insights of this reaction have been given and the authors have proposed the intermediate 138 , displaying minimised steric interactions and leading to the major desymmetrized adduct 139 38.…”

Stoichiometric asymmetric processes

“…341 Enantiomerically pure C 2 symmetric keto sulfoxides have been used to prepare symmetrical acetals 70 that undergo base-promoted asymmetric ring opening reactions giving the benzyl ether 71 in excellent yield and diastereomeric excess (Scheme 46). 342,343 Chiral oxazolidines derived from (R)-phenylglycinol react with dialkylalkynylalane-triethylamine complexes giving alkynylamines in excellent diastereomeric excess 344 while enantiopure substituted pyrrolidines may be prepared by the reduction of chiral bicyclic oxazolidines with LiBHEt 3 . 345 A number of miscellaneous reactions of organometallic reagents other than addition to carbonyl compounds have been reported.…”