Efficient desymmetrization of 4,6-di-O-benzyl-myo-inositol by Lipozyme TL-IM

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.

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.

Resolution of orthogonally protected myo-inositols with novozym 435 providing an enantioconvergent pathway to Ac2PIM1

Orthogonally protected chiral myo-inositol derivatives are important intermediates for higher order myo-inositol-containing compounds. Here, the use of the immobilized enzyme Novozym 435 to efficiently catalyze the acetylation of the 5R configured enantiomer of racemic 1,2-O-isopropylidene-myo-inositols possessing chemically and sterically diverse protecting groups at O-3 and O-6 is described. The resolutions were successful with allyl, benzyl, 4-bromo-, 4-methoxy-, 4-nitro-, and 4-(3,4-dimethoxyphenyl)benzyl, propyl, and propargyl protection at O-6 in combination with either allyl or benzyl groups at O-3. Bulky protecting groups slow the rate of acetylation. No reaction was observed for 3,6-di-O-triisopropylsilyl-1,2-O-isopropylidene-myo-inositol. The utility of this methodology was demonstrated by the first reported synthesis of an Ac2PIM1 (9), which used both enantiomers of the resolved 3-O-allyl-6-O-benzyl-1,2-O-isopropylidene-myo-inositol in a convergent synthesis.