5673-98-3Relevant academic research and scientific papers
Enantiopure 2,9-Dideuterodecane – Preparation and Proof of Enantiopurity
Christoffers, Jens,Eru?ar, Gülsera,Fsadni, Miriam H.,Golding, Bernard T.,Mitschke, Nico,Roberts, Amy R.,Sadeghi, Majid M.,Wilkes, Heinz
, p. 3854 - 3863 (2021/08/24)
(R,R)- and (S,S)-(2,9-2H2)-n-Decane were prepared regio- and stereospecifically in 25–26 % yield over five steps from commercially available enantiopure (R)- and (S)-propylene oxide, respectively. The synthetic procedure involved nucleophilic displacement of (R)- and (S)-4-toluenesulfonic acid 1-methyl-4-pentenyl ester with LiAlD4 to furnish the respective (5-2H)-1-hexenes. Subsequent olefin metathesis and reduction of the double bond furnished the title compounds. The optical purity of (R,R)- and (S,S)-(2,9-2H2)-n-decane could not be determined by chromatography or polarimetry. Therefore, (R,R)- and (R,S)-(5-2H)-3-hydroxy-2-hexanone were prepared from their respective hexenes by Wacker oxidation, followed by enantioselective α-hydroxylation. The enantiopurity could then be determined by NMR spectroscopy because the stereospecifically deuterated hydroxyketones showed separated signals for the subterminal carbon atom (C-5) in the 13C NMR spectrum.
Chiral Acetals as Stereoinductors: Diastereoface Selective Alkylation of Dihydrobenzoxazine-Derived Amide Enolates
Mulzer, Johann,Langer, Oliver,Hiersemann, Martin,Bats, Jan W.,Buschmann, Juergen,Luger, Peter
, p. 6540 - 6546 (2007/10/03)
Novel dihydrobenzoxazine-derived acetals of type 3 have been developed for asymmetric C-alkylations of propionyl amide enolates. High stereoselectivities are obtained for amides 15 and 22 which are rationalized in terms of intramolecular metal chelate formation.
Syntheses of (-)-epothilone B
Schinzer, Dieter,Bauer, Armin,Schieber, Jennifer
, p. 2492 - 2500 (2007/10/03)
Two efficient routes for the total synthesis of (-)-epothilone B are reported. One strategy is based on ring-closing metathesis, and a second synthesis on a macrolactonization. The key fragments are available on large scale to provide sufficient material for biological tests. Thiazole fragment 4 was obtained by an improved route starting from (S)-malic acid. The first synthesis is based on our preceding paper. The critical trisubstituted double bond C12-13 in our second approach was constructed by a highly efficient Pd- mediated coupling reaction. Ring closure was achieved by macrolactonization.
Facile and selective alkylation of 3,3,3-trifluoropropene oxide (TFPO) with organoaluminum reagents via pentacoordinate trialkylaluminum complexes
Ooi, Takashi,Furuya, Mayumi,Maruoka, Keiji
, p. 817 - 818 (2007/10/03)
A new organoaluminum-promoted selective alkylation of 3,3,3-trifluoropropene oxide (TFPO) with several nucleophiles has been developed which involves the chelation-activated addition to fluoro epoxides via pentacoordinate trialkylaluminum complexes.
Allyltitanium Triphenoxide: Selective Cleavage of Oxiranes at the More Substituted Carbon Atom
Tanaka, Tetsuaki,Inoue, Tetsuya,Kamei, Katsuhide,Murakami, Kazuo,Iwata, Chuzo
, p. 906 - 908 (2007/10/02)
Allyltitanium triphenoxide was found to be an excellent reagent for regioselective allylation at the more substituted carbon atom of oxiranes.
Total synthesis of the polyether antibiotic X-206
Evans,Bender,Morris
, p. 2506 - 2526 (2007/10/12)
A convergent asymmetric synthesis of the polyether antibiotic X-206 has been achieved through the synthesis and coupling of the C1-C16- and C17-C37 synthons 16 and 17, respectively. All absolute stereochemical relationships within the molecule were controlled by application of recent methodological advances in asymmetric synthesis. In the synthesis of subunit 16, both the alkylation and aldol reactions of chiral imide-derived enolates were utilized to establish the five stereogenic centers at C2-C4 and C9-C10, while the stereochemistry at C14 was indirectly controlled by the Sharpless asymmetric epoxidation. The C7 and C11 stereocenters, which are situated at the two assemblage points for 16, were established through internal asymmetric induction. The synthesis of the more complex C17-C37 subunit 17 followed a similar strategy for absolute stereocontrol. Chiral enolate methodology was employed to define the stereogenic centers at C18, C22, and C23 while asymmetric epoxidation was used to create the oxygen-bearing centers at C30-C31 and C34-C35. The remaining three stereogenic centers at C20, C26, and C28 were controlled by internal asymmetric induction. The successful construction of this synthon relied upon the development of an efficient assemblage reaction in which three fragments comprising the entire carbon framework of 17 were united in a single operation. The final coupling of the two halves was achieved by a nonstereoselective aldol reaction. In supporting studies, the selective manipulation and degradation of the natural product were also investigated.
Camphorsulfonamide-Shielded, Asymmetric 1,4-Additions and Enolate Alkylations; Synthesis of a Southern Corn Rootworm Pheromone
Oppolzer, Wolfgang,Dudfield, Philip,Stevenson, Thomas,Godel, Thierry
, p. 212 - 215 (2007/10/02)
Using readily accessible 10-sulfonamido-isoborneols as regenerable, chiral auxiliaries, highly face-selective C-C-bond formations at Cα and Cβ of carboxylates could be conveniently achieved.Thus, conjugated additions of RCu to enoates (1->2) furnished, after saponification, β-substituted carboxylic acids 3 in 94-98 percent e.e.Similarly, propionates 12 yielded after deprotonation, enolate alkylation, and reductive ester cleveage the (R)-alcohols 15 in 78-98 percent e.e.The acid (+)-3e was converted to the pheromone (-)-11.
