Highly Stereoselective Construction of Carbon-Carbon Bonds  Using Phosphonyl and Phosphoramidite Auxiliaries            (Chemistry)
{'Code': '03090003', 'Directorate': {'Abbreviation': 'MPS', 'LongName': 'Direct For Mathematical & Physical Scien'}, 'Division': {'Abbreviation': 'CHE', 'LongName': 'Division Of Chemistry'}}
{'SignBlockName': 'George M. Rubottom', 'PO_EMAI': None, 'PO_PHON': None}
This research is being supported by the Organic and                             Macromolecular Chemistry Program.  The synthesis of the complex                 structures that occur in nature requires the development of                     highly specific reactions.  This work will produce new reagents                 based on the unique reactivity produced by a phosphorous atom.                                                                                                  Investigations centering on (i) highly stereoselective Aldol                    reactions (both acid and base-mediated) with                                    alpha-acylphosphonate diesters, (ii) stereochemical control of                  the Mukaiyama-Michael reaction, and (iii) the stereoselective                   alkylations of chiral phosphoramidite homoenolate anion                         synthons are described.  The central feature of this three-part                 research program is the establishment of a highly                               stereoselective methodology for construction of carbon-carbon                   bonds within acyclic molecules.  Both high diastereofacial and                  enantiofacial selectivity is predicted based on the                             stereochemistry and steric bulk of the auxiliary as well as                     intramolecular metal ion complexation ability.                                                                                                                  Specifically, the metal anions of                                               alpha-acyl-1,3,2-dioxaphosphonates are used to control enolate                  geometry and diasteromer preference when alkylated.                             Introduction of chirality into the 1,3,2-dioxaphosphonyl                        skeleton creates potential for asymmetry transfer from the                      chiral auxiliary.  Examination of transition state models                       provide insight into factors likely to control                                  diastereoselectivy.  Finally, condensation of chiral                            phosphoramidities derived from (1S,2R)-(+)-ephedrine and                        (E)-3-phenylpropenal or crotonaldehyde provide substrates                       suitable for chelation-controlled enantioselective alkylation                   of the prochiral organometallic intermediate.
{'FirstName': 'Slayton', 'LastName': 'Evans', 'PI_MID_INIT': 'A', 'PI_SUFX_NAME': 'Jr.', 'PI_FULL_NAME': 'Slayton A Evans', 'EmailAddress': None, 'NSF_ID': '000354474', 'StartDate': '03/01/1988', 'EndDate': None, 'RoleCode': 'Principal Investigator'}
{'Name': 'University of North Carolina at Chapel Hill', 'CityName': 'CHAPEL HILL', 'ZipCode': '275995023', 'PhoneNumber': '9199663411', 'StreetAddress': '104 AIRPORT DR STE 2200', 'StreetAddress2': None, 'CountryName': 'United States', 'StateName': 'North Carolina', 'StateCode': 'NC', 'CONGRESSDISTRICT': '04', 'CONGRESS_DISTRICT_ORG': 'NC04', 'ORG_UEI_NUM': 'D3LHU66KBLD5', 'ORG_LGL_BUS_NAME': 'UNIVERSITY OF NORTH CAROLINA AT CHAPEL HILL', 'ORG_PRNT_UEI_NUM': 'N8DMK1K4C2K5'}
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[{'Code': '1948', 'Text': 'SYNTHESIS'}, {'Code': '1950', 'Text': 'METHODOLOGY'}]
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