Organic Chemistry: Multistep Synt#hsis, New Synthetic Methodology, Exploratory Chemistry

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This program, supported by the Organic and Macromolecular section covers a broad area of synthetic organic chemistry.The synthesis by multistep processes of several naturally occurring and biologically active complex organic molecules is under study. Most of the molecules under study are of unusual interest because of their biological activities. Some may be of value in the development of new human therapeutic agents. Hand in hand with the objective of achieving simple and effective syntheses of specific target structures is the development of new general synthetic organic reactions and methods and demonstrating their usefulness in the chosen multistep synthetic problems. The discovery of such methods amplifies the power of synthesis and extends its range of application to ever more formidable structures. In the course of this effort, a deeper appreciation of various fields of chemistry, e.g. organometallic chemistry and chemical theory, can be gained. In the area of multistep synthesis the following specific projects are being carried out: (1) synthesis of chiral C15 gingkolides; bilobalide and analogs; (2) synthesis of chiral C20 gingkolides and analogs; (3) synthesis of kadsuranone and other antagonists of platelet activating factor (PAF ac ether, or simply PAF); (4) synthesis of preclavulone-A and more complex marine eicosanoids derived therefrom; (5) synthesis of pseudopterosin; (6) synthesis of glycinoeclepin; (7) synthesis of venustatriol; (8) synthesis of biotin; (9) synthesis of protosterol; (10) synthesis of tricyclohexaprenol. In the areas of new synthetic methodology a number of projects are directed at the important problem of enantioselectivity in synthesis including the following: (1) further studies to extend and broaden the important discovery of catalytic, enantioselective reductions by borane; (2) enantioselective 1,2 -addition of carbon to aldehydes and ketones; (3) enantioselective conjugate addition of cuprates and other organometallic reagents to enones; (4) catalytic enantioselective cyclopropanation; (5) new chiral controller groups and reagents. Finally, a number of new methods will be studied which ultimately will lead to new and practical methods of oxidation, C-C bond formations, and ring formation reactions.