Desymmetrization of 4,6-diprotected myo-inositol

Enantioselective Synthesis of Nabscessin C

Enantioselective synthesis of nabscessin C (1), an aminocyclitol amide with antimicrobial activity, is reported. Starting from myo-inositol, (+)-nabscessin C was synthesized in 12 isolation steps. Desymmetrization of 2-deoxygenated 4,6-dibenzylinositol was achieved using lipase from porcine pancreas (PPL), and the stereochemistry was established by X-ray crystallography. This method has the potential for synthesizing other cyclitol-derived compounds.

Catalytic Approaches to Chemo- and Site-Selective Transformation of Carbohydrates

Carbohydrates are a fundamental unit playing pivotal roles in all the biological processes. It is thus essential to develop methods for synthesizing, functionalizing, and manipulating carbohydrates for further understanding of their functions and the creation of sugar-based functional materials. It is, however, not trivial to develop such methods, since carbohydrates are densely decorated with polar and similarly reactive hydroxy groups in a stereodefined manner. New approaches to chemo- and site-selective transformations of carbohydrates are, therefore, of great significance for revolutionizing sugar chemistry to enable easier access to sugars of interest. This review begins with a brief overview of the innate reactivity of hydroxy groups of carbohydrates. It is followed by discussions about catalytic approaches to enhance, override, or be orthogonal to the innate reactivity for the transformation of carbohydrates. This review avoids making a list of chemo- and site-selective reactions, but rather focuses on summarizing the concept behind each reported transformation. The literature references were sorted into sections based on the underlying ideas of the catalytic approaches, which we hope will help readers have a better sense of the current state of chemistry and develop innovative ideas for the field.

Total Synthesis of Antiausterity Agent (±)-Uvaridacol L by Regioselective Axial Diacylation of a myo-Inositol Orthoester

The antiausterity natural product (±)-uvaridacol L was synthesized for the first time in seven steps from myo-inositol. The key reaction of this synthesis, axial selective dibenzoylation of myo-inositol orthoformate, was achieved using a catalytic amount of tetrabutylammonium fluoride (TBAF). The preferential cytotoxicity of racemic uvaridacol L against cancer cell lines able to adapt to nutrient deprivation was also evaluated under nutrient deprived conditions. Morphological evaluation was also carried out.

Development of isotope-enriched phosphatidylinositol-4- and 5-phosphate cellular mass spectrometry probes

Synthetic phosphatidylinositol phosphate (PtdInsP_n) derivatives play a pivotal role in broadening our understanding of PtdInsP_n metabolism. However, the development of such tools is reliant on efficient enantioselective and regioselective synthetic strategies. Here we report the development of a divergent synthetic route applicable to the synthesis of deuterated PtdIns4P and PtdIns5P derivatives. The synthetic strategy developed involves a key enzymatic desymmetrisation step using Lipozyme TL-IM®. In addition, we optimised the large-scale synthesis of deuterated myo-inositol, allowing for the preparation of a series of saturated and unsaturated deuterated PtdIns4P and PtdIns5P derivatives. Experiments in MCF7 cells demonstrated that these deuterated probes enable quantification of the corresponding endogenous phospholipids in a cellular setting. Overall, these deuterated probes will be powerful tools to help improve our understanding of the role played by PtdInsP_n in physiology and disease.

We report the synthesis of deuterium-labelled derivatives of phosphatidylinositol 4-phosphate and phosphatidylinositol 5-phosphate, and demonstrate their use in quantifying levels of endogenous phospholipids in cells.

Regio/Site-Selective Benzoylation of Carbohydrates by Catalytic Amounts of FeCl3

This work uncovered the regio/site-selective benzoylation of 1,2- and 1,3-diols and glycosides containing a cis-vicinal diol using a catalytic amount of FeCl3 with the assistance of acetylacetone. FeCl3 may initially form [Fe(acac)3] (acac = acetylacetonate) with excess acetylacetone in the presence of diisopropylethylamine (DIPEA) in acetonitrile at room temperature. Then, benzoylation was catalyzed by Fe(acac)3 with added benzoyl chloride in the presence of DIPEA under mild conditions as reported. This reaction produced selectivities and isolated yields similar to or slightly lower than the reaction using Fe(acac)3 as a catalyst in most cases. The result provides not only the green and convenient selective benzoylation method associated with the most inexpensive catalysts but also the possibility that the effects of various metal salts and ligands on the regioselective protection can be extensively investigated in future study to obtain the optimized catalytic system.

Labeling of Phosphatidylinositol Lipid Products in Cells through Metabolic Engineering by Using a Clickable myo-Inositol Probe

Phosphatidylinositol (PI) lipids control critical biological processes, so aberrant biosynthesis often leads to disease. As a result, the capability to track the production and localization of these compounds in cells is vital for elucidating their complex roles. Herein, we report the design, synthesis, and application of clickable myo-inositol probe 1 a for bioorthogonal labeling of PI products. To validate this platform, we initially conducted PI synthase assays to show that 1 a inhibits PI production in vitro. Fluorescence microscopy experiments next showed probe-dependent imaging in T-24 human bladder cancer and Candida albicans cells. Growth studies in the latter showed that replacement of myo-inositol with probe 1 a led to an enhancement in cell growth. Finally, fluorescence-based TLC analysis and mass spectrometry experiments support the labeling of PI lipids. This approach provides a promising means for tracking the complex biosynthesis and trafficking of these lipids in cells.

Inositol to aromatics -benzene free synthesis of poly oxygenated aromatics

A method for the preparation of benzene derivatives from myo-inositol, an abundantly available phyto chemical is described. 1,3-Bridged acetals of inososes undergo step-wise elimination leading to the formation of polyoxygenated benzene derivatives. This aromatization reaction proceeds through the intermediacy of a β-alkoxyenone, which could be isolated. This sequence of reactions starting from myo-inositol, provides a novel route for the preparation of polyoxygenated benzene derivatives including polyoxygenated biphenyl. This scheme of synthesis demonstrates the potential of myo-inositol as a sustainable non-petrochemical resource for aromatic compounds.

Yb(OTf)3-Catalyzed Desymmetrization of myo-Inositol 1,3,5-Orthoformate and Its Application in the Synthesis of Chiral Inositol Phosphates

A variety of inositol phosphates including myo-inositol 1,4,5-trisphosphate, which is a secondary messenger in transmembrane signaling, were selectively synthesized via Yb(OTf)₃-catalyzed desymmetrization of myo-inositol 1,3,5-orthoformate using a proline-based chiral anhydride as an acylation precursor. The investigated catalytic system could regioselectively differentiate the enantiotopic hydroxy groups of myo-inositol 1,3,5-orthoformate in the presence of a chiral auxiliary. This key step to generate a suitably protected chiral myo-inositol derivatives is described here as a unified approach to access inositol phosphates.