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Chemistry and Biochemistry
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Part I. Alkylation reactions of the camphor imine of t-butyl gly- cinate 1 were found to proceed with varing amounts of diastereo- facial selectivity depending on the electronic nature of the alkylating agent. Saturated alkyl halides gave diastereomeric excesses up to 67%. Allylic and benzylic alkylating agents reacted to provide diastereomeric excesses up to 98%. A transition state model which involves a favorable electronic interaction between the pi system of the alkylating agent and the lithium enolaate has been proposed to explain the enhanced diastereoselectivities observed for these types of alkylating agents. (DIAGRAM, TABLE OR GRAPHIC OMITTED...PLEASE SEE DAI) (UNFORMATTED TABLE FOLLOWS) NCH(,2)CO(,2)t-Bu NCHCO(,2)t-Bu 1 R(TABLE ENDS) (1-Bromoethyl)benzene, 3-bromocyclohexene, and 5,5-dimethyl- 3-bromocyclohexene were found to react to give only two of the four possible diastereomers. It was determined that the stereochemically pure center of the products from these reactions was C-3 (by amino acid numbering). Palladium mediated allylation reactions of the sodium enolate of 1 were also possible. Part II. Attempts to capture the sulfur stabilized carbonium ion intermediate of the Pummerer reaction of 1,3-oxathiolan-5-ones and 1,3-thiazolidin-4-ones with olefins and benzene are described. The reactions were unsuccessful with the oxathiolanones studied. Substi- tutions at the 5-position of 3-methyl-1,3-thiazolidin-4-one have been achieved using trifluoroacetic anhydride as the catalyst. 5-Phenyl substitutions of all thiazolidinones were easily performed utilizing an excess amount of concentrated sulfuric acid as the catalyst. Aldol and alkylation reactions of the 3-methyl-thiazolidinone were also successful. Source: Dissertation Abstracts International, Volume: 47-09, Section: B, page: 3750. Thesis (Ph.D.)--University of Windsor (Canada), 1986.
LEAVITT, RANDALL K., "PART I. ELECTROPHILE STRUCTURE AS A FACTOR IN ALKYLATIONS OF CAMPHOR DERIVATIZED GLYCINATES. PART II. PUMMERER REACTIONS OF S-OXIDES OF 1,3-OXATHIOLAN-5-ONES AND 1,3-THIAZOLIDIN-4-ONES." (1986). Electronic Theses and Dissertations. 3003.