Catalytic asymmetric Michael/cyclization reaction of 3-isothiocyanato thiobutyrolactone: an approach to the construction of a library of bispiro[pyrazolone-thiobutyrolactone] skeletons
Here, we demonstrate the first example of 3-isothiocyanato thiobutyrolactone serving as a useful building block in the Michael/cyclization reaction with alkylidene pyrazolones for the enantioselective construction of optically active structural bispiro[pyrazolone-thiobutyrolactone] skeletons containing three contiguous stereocenters with two spiroquaternary stereocenters. These products were smoothly
在这里,我们展示了 3-异硫氰酸基硫代丁内酯的第一个例子,它在与亚烷基吡唑啉酮的迈克尔/环化反应中用作有用的结构单元,用于对映选择性构建包含三个连续立体中心和两个螺季四元立体中心的光学活性结构双螺[吡唑酮-硫代丁内酯]骨架. 这些产品在温和条件下以手性方甲酰胺作为催化剂以高达 90% 的产率、>20:1 dr 和 >99% ee 顺利提供。值得注意的是,这也是螺环吡唑啉酮支架与螺环硫代丁内酯支架合并的第一个例子,可能在药物化学中有用。
Spirocyclization and Michael addition of 3-benzylidene succinimides: route to spirocyclopentapyrrolidine-tetraones and benzylidene <i>N</i>-arylpyrrolidine-diones
作者:Pooja Dahiya、Anoop Yadav、Rama Krishna Peddinti
DOI:10.1039/d3ob01629c
日期:——
Reactions of 3-benzylidene succinimides with 2-substituted 2-hydroxy-indane-1,3-diones and unsaturated pyrazolones are carried out under basic conditions to afford spirocyclized derivatives and Michael adducts, respectively, with high regio- and stereo-selectivities. The most notable aspect of the reaction is the ability of highly reactive benzylidene succinimide to act as both an electrophile and
A new method to generate a series of spiro-pyrazolone-tetrahydrofurans/pyrans is developed by using a base-mediated cascade ipso-cyclization of unsaturated pyrazolones and haloalcohols. Noteworthy aspects of this methodology include its brief reaction duration, expansive substrate applicability, very good yields, and mild reaction conditions without the need for transition metals. Interestingly, the
Phosphine-catalyzed [4 + 2] cycloaddition of unsaturated pyrazolones with allenoates providing concise access to spiropyrazolones.
磷催化的[4 + 2]环加成反应,将不饱和吡唑酮与烯酸酯进行反应,简洁地合成螺环吡唑酮。
Sonochemical synthesis of benzylidene derivatives of enolizable carbonyls and their analogues in aqueous ethanol
作者:Palak J. Patel、Hiren R. Chaudhary、Vivek K. Gupta、Divyang M. Patel
DOI:10.1007/s11164-023-05168-3
日期:2024.3
benzylidene derivatives via a direct sp3 C–H olefination reaction of enolizable carbonyls. We remarkably emphasize the synthetic utility of these derivatives and validate the molecular structures using 1H-NMR and 13C-NMRspectroscopy (APT) as well as SC-XRD investigation of representative compounds. Graphical abstract