has been isolated and subsquently synthesized in enantiomerically pure form. The total synthesis includes a Sharpless asymmetric dihydroxylation protocol as the stereodifferentiating step, followed by two diastereoselective aldol-type reactions. The approach allows the unambiguous control of all three stereogenic centres, and, furthermore, unequivocal determination of the relative and absolute configuration
Stereoselective total syntheses of (−)-hygrophorone A<sup>12</sup>, 4-<i>O</i>-acetyl-hygrophorone A<sup>12</sup> and (+)-hygrophorone B<sup>12</sup>
作者:Sayani Das、Anu Dalal、Shivajirao L. Gholap
DOI:10.1039/d0ob02303e
日期:——
Totalsyntheses of anti-fungal cyclopentenones (−)-hygrophorone A12, 4-O-acetyl-hygrophorone A12 and (+)-hygrophorone B12 were achieved in high overall yields from D-(−)-tartaric acid. The key feature of these syntheses is the aqueous KOH-mediated diastereoselective intramolecular aldol reaction to form β-hydroxy ketone with three contiguous chiral centres, which was further elaborated to (−)-hygrophorone
Structural and stereochemical elucidation of new hygrophorones from Hygrophorus abieticola (Basidiomycetes)
作者:Alexander Otto、Andrea Porzel、Bernhard Westermann、Wolfgang Brandt、Ludger Wessjohann、Norbert Arnold
DOI:10.1016/j.tet.2017.02.013
日期:2017.3
Four new hygrophorones (1–4) together with the known hygrophorone B12 (5) have been isolated fromfruitingbodies of the basidiomycete Hygrophorus abieticola Krieglst. ex Gröger & Bresinsky. Their structures were assigned on the basis of extensive one and two dimensional NMR spectroscopic analyses as well as ESI-HRMS measurements. Among these compounds, two previously undescribed hygrophorone types
四个新hygrophorones(1 - 4)与已知的hygrophorone B一起12(5)已经从担子菌的子实体中分离Hygrophorus abieticola Krieglst。前Gröger和Bresinsky。根据广泛的一维和二维NMR光谱分析以及ESI-HRMS测量,确定了它们的结构。在这些化合物中,鉴定出两种先前未描述的潮气固酮类型,称为潮气固酮H 12(3)和2,3-二氢潮气固酮H 12(4)。Hygrophorone E 12(2的绝对构型)的建议是基于量子化学CD计算,而半合成方法结合计算研究和NOE相互作用的分析允许化合物3和4的立体化学分配。此外,通过羟基的乙酰化生成了潮气酮B 12(5)的半合成衍生物。评估了天然和半合成的潮菌酮对植物致病生物的生物学活性,发现α,β-不饱和羰基官能团可能是必不可少的结构特征。Hyphorphorone B 12(5)被认为是活性