Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 5 of 5 for “"chiral methyl"”.
-
Investigation of the Stereochemistry of the Methyl-to-Methylene Elimination in the Biosynthesis of Several Terpenes Through the Use of Chiral Methyl Labeled Compounds
The synthesis of (R)- (13-$\sp2$H, $\sp3$H) farnesyl diphosphate has been completed by methodology similar to that used for the synthesis of (R)- (9-$\sp2$H, $\sp3$H) geranyl diphosphate. Incubation of the radiolabeled farnesyl diphosphate with 5-epi-aristolochene synthase gave the ($\sp2$H, …
-
Stereochemistry and Mechanism of the Enzyme -Catalyzed Cyclizations of Farnesyl Diphosphate to the Sesquiterpenes Epi -Aristolochene, Epi-Eremophilene and Vetispiradiene
Chiral methyl FPPs were prepared by the displacement of allylic monodeuterated diethyl phosphates with LiBEt3T. (12R)- and ( 12S)-[12-2H1, 12-3H 1]FPPs were incubated with TEAS, and the 3H NMR spectra showed that several tritiated compounds were present. The facial selectivity of the proton …
-
Stereochemistry and Mechanism of the Enzyme-Catalyzed Cyclization of Geranylgeranyl Diphosphate to (-)-Abietadiene
… abietadiene where the stereochemistry of the methyl was established as R by degradation and enzymatic analysis of the generated chiral methyl acetic acid. This indicated a surprising syn facial relationship of the ""intramolecular"" proton transfer and methyl migration on the si face of the …
-
Lewis Base Catalyzed Aldol Additions of Chiral Silyl Enol Ethers and Total Synthesis of Rk-397
The double diastereodifferentiation in chiral Lewis base catalyzed aldol additions was examined using chiral silyl enol ethers derived from hydroxyisobutyrate and hydroxybutyrate. Trichlorosilyl enolates derived from the chiral methyl and ethyl ketones were subjected to the Lewis base catalyzed …
-
Investigations of metalloenzymes involved in bacterial natural product biosynthesis
… enzyme Fom3 from Streptomyces wedmorensis, a methyltransferase in the radical S-adenosylmethionine (SAM) superfamily, with its required iron-sulfur cluster and cobalamin (B12) cofactors. The methyl transfer reaction catalyzed by Fom3 was then investigated in vitro using a combination of …