The diastereoselective nucleophilic trifluoromethylation of a range of ketoamides derivedfrom L-tartaric acid has been studied. TMSCF3 in the presence of a catalytic amount of K2CO3 in DMF has been identified as the conditions leading to the highest diastereoselectivities. A sequential one-pot reaction trifluoromethylation-etherification of the trifluoromethylcarbinol has been developed. Only one
Synthesis of Enantiopure Trifluoromethyl Building Blocks via a Highly Chemo- and Diastereoselective Nucleophilic Trifluoromethylation of Tartaric Acid-Derived Diketones
acid-based diketone, using trifluoromethyl(trimethyl)silane, afforded the corresponding γ-keto trifluoromethylcarbinol. The scope and limitation of this reaction was studied. The acidic removal of the acetonide moiety protecting the two hydroxyl groups of the adducts was unsuccessful. Bis(O-methylation) of the aromatic derivatives under basic conditions, followed by acidic hydrolysis and oxidative cleavage
Asymmetric synthesis of both enantiomers of α-methyl-α-methoxyphenylacetic acid from l-(+)-tartaric acid: formal enantioselective synthesis of insect pheromone (−)-frontalin
作者:Kavirayani R. Prasad、Appayee Chandrakumar、Pazhamalai Anbarasan
DOI:10.1016/j.tetasy.2006.07.007
日期:2006.8
Both antipodes of α-methyl-α-methoxyarylacetic acid derivatives were prepared from a common chiralpool precursor l-(+)-tartaricacid. The key step involves the addition of Grignard reagents to 1,4-diketones derived from tartaric acid. The utility of this strategy was applied in the formal enantioselective synthesis of pine beetle pheromone (−)-frontalin.
Nucleophilic Addition Reactions of 1,4-Diketones Derived from Tartaric Acid: Synthesis of TADDOL Analogues
作者:Kavirayani Prasad、Appayee Chandrakumar
DOI:10.1055/s-2006-942422
日期:2006.7
A systematic investigation of the reduction and Grignard reagents addition to 1,4-diketones derived from tartaric acid was carried out. It was found that the reduction proceeded with high selectivity using K-Selectride as the reducing agent; while Grignard reagent addition was highly dependent on structure of the dione as well as on the Grignard reagent. The resultant 1,4-diols represent a series of novel TADDOL analogues.