ASYMMETRIC SYNTHESIS OF 1,3-POLYOLS VIA HYDROSILATION

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The proposed research explores a novel methodology for the synthesis of 1,3-diol and 1,3,5-triol functionalities via the intramolecular hydrosilation of homoallylic alcohols. Alkene facial selectivity is afforded by the use of a chiral auxiliary (aC2 symmetric binaphthol) attached to the silicon atom of the starting material. It is proposed that the chiral auxiliary will then be able to be further utilized in relaying stereochemical information throughout the product in subsequent transformations. Thus through further functionalization and manipulation 1,3-polyol functionalities should be produced. In such a way, it is proposed that the chiral auxiliary can control the absolute stereochemistry of three centers before being cleaved from the product and recycled. The importance of 1,3-polyols is born out in their vast presence in the natural product world. Several antibiotic, anti-tumor and immunosuppressant compounds contain this functionality. One such compound, (-) discodermolide, contains three 1,3,5-triol units, one of which should be accessible using the proposed methodology. To further explore the scope of silicon tethered methodology, it is proposed that all three building blocks be made using variations of the hydrosilation methodology, and an important connection in making the backbone of the natural product be performed using a silicon tethered alkene ring closing metathesis protocol.