115118-85-9Relevant academic research and scientific papers
Enantiopure building blocks for the synthesis of 3-methyl-2-alkanols. Diastereoselective methylmetal addition to a chiral 2-methylaldehyde followed by lipase catalysed esterification
Larsson, Michael,Andersson, Jimmy,Liu, Rong,Hoegberg, Hans-Erik
, p. 2907 - 2915 (2007/10/03)
The racemic synthetic building block (2R*,3R*)-3-methyl-4- (phenylsulfanyl)butan-2-ol (2R*,3R*)-2 was obtained in a high diastereomeric ratio [95:5, (2R*,3R*)/(2R*,3S*)-ratio] by Lewis acid catalysed dimethylzinc addition to racemic 2-methyl-3- (phenylsul
Enantioselective Total Synthesis of (-)-Monic Acid C via Carbosulfenylation of Dihydropyran
White, James D.,Theramongkol, Parinya,Kuroda, Chiaki,Engebrecht, Jeffrey R.
, p. 5909 - 5921 (2007/10/02)
A stereoselective synthesis of (-)-monic acid C (5) was accomplished in a linear sequence of 22 steps beginning from dihydropyran and with (-)-1-borneol as a chiral auxiliary. 2-(1-Bornyloxy)pyrans 10 and 11 were converted via trans epoxides 12 and 13 to hydroxy selenides 16 and 17.Selenide 16 was transformed to vinyl ether 20, which underwent Claisen rearrangement to 22.The latter, after oxidation to carboxylic acid 24, was treated with stannic chloride to give the γ-lactone 26.A parallel sequence from 17 brought this selenide, via 29 and its Claisen rearrangement product 31, into convergence with 26.Carbosulfenylation of 26 in the presence of 2-(trimethylsiloxy)propene was accompanied by elimination and led to 33 and its trans isomer 34.Cis hydroxylation of 33, protection of the resulting diol, and Horner-Emmons condensation of 41 with tert-butyl dimethyl-phosphonoacetate gave 43.Attachment of the second side chain of 5 was effected by means of a Julia olefination of 46 with sulfone 65, prepared from ethyl (2S,3S)-3-hydroxy-2-methylbutanoate.The resulting substituted tetrahydropyran 68, after removal of the three protecting groups, yielded 5.
Total Synthesis of Pseudomonic Acid C
Barrish, Joel C.,Lee, Hsi Lin,Mitt, Toomas,Pizzolato, Giacomo,Baggiolini, Enrico G,Uskokovic, Milan R
, p. 4282 - 4295 (2007/10/02)
Two approaches to the synthesis of aldehyde 28, a key intermediate in the total synthesis of pseudomonic acid C, were developed.One asymmetric route from the chiral hydroxy ester 11 proceeded in 13 steps via the hydroxy lactone 17.A shorter approach involved the Lewis acid catalyzed cycloaddition of formaldehyde to the chiral diene 23a to give 22a, which was separated from its diastereomer and then converted into 28 in seven steps.The introduction of the C-8 side chain was initially accomplished by Julia coupling of 28 with the sulfone anion derived from 40 to give the olefin 34.The stereoselective preparation of 34 was also carried out, via the ester 46a, by a novel ester enolate Claisen rearrangement of the silyl-protected glycolate ester 44.A third approach directed toward the synthesis of the side chain entailed controlling the C-10 stereochemistry of the benzyl-protected glycolate ester 48 by reduction of a precursor propargyl ketone 27 with Alpine borane.Ester enolate Claisen rearrangement then gave the ester 46b with excellent stereocontrol.
Total Synthesis of Pseudomonic Acid C
Keck, Gary E.,Kachensky, David F.,Enholm, Eric J.
, p. 1462 - 1464 (2007/10/02)
A convergent total synthesis of pseudomonic acid C from L-lyxose is described in which a highly stereoselective free-radical C-C bond construction plays a key role.
