Huang, Pei-Qiang Wu, Tian-Jun Ruan, Yuan-Ping A Flexible Approach to (<i>S</i>)-5-Alkyl Tetramic Acid Derivatives:  Application to the Asymmetric Synthesis of (+)-Preussin and Protected (3<i>S</i>,4<i>S</i>)-AHPPA A flexible asymmetric approach to 5-alkyl tetramic acid derivatives is described, which is based on the use of <b>9</b> as the first synthetic equivalent to chiral nonracemic tetramic acid 5-carbanionic synthon <b>9b</b>. The existence of the carbanion intermediate <b>9b</b> was proven by trapping with trimethylchlorosilane. Application of the present method to the synthesis of antifungal alkaloid (+)-preussin, as well as protected (3<i>S</i>,4<i>S</i>)-AHPPA <b>6</b>, is also described. alkaloid;Application;Flexible Approach;Preussin;Derivative;acid;tetramic;carbanion;application;nonracemic;derivative;approach;method;9 b;synthon;Asymmetric Synthesis;Alkyl;equivalent;preussin;AHPPA;antifungal;Protected;carbanionic;chiral;alkyl;synthesis;Tetramic;trimethylchlorosilane 2003-11-13
    https://acs.figshare.com/articles/journal_contribution/A_Flexible_Approach_to_i_S_i_5_Alkyl_Tetramic_Acid_Derivatives_Application_to_the_Asymmetric_Synthesis_of_Preussin_and_Protected_3_i_S_i_4_i_S_i_AHPPA/3359881
10.1021/ol035617a.s001