69056-12-8Relevant articles and documents
A SHORT AND STEREOSELECTIVE SYNTHESIS OF THE (+/-) PRELOG-DJERASSI LACTONIC ACID
Maruyama, Kazuhiro,Ishihara, Yuji,Yamamoto, Yoshinori
, p. 4235 - 4238 (1981)
Reaction of meso-4-carbomethoxy-2-methylpentanal (1) with crotyltri-n-butyltin at -78 deg C in the presence of 1 eq BF3*OEt2, followed by the lactonization with BF3*OEt2, gave 6-(1-methylallyl)-3,4,5,6-tetrahydro-3,5-dimethyl-2-pyranone (2a) with the correct stereochemistry (erythro, anti-Cram) in 92percent yield, which was converted to the title compound (3) in 85percent yield upon the ozonolytic cleavage of the double bond.
Enantioselective synthesis of the Prelog-Djerassi lactonic acid via group-selective aldolization/desymmetrization of a meso dialdehyde with a chiral N-propionylsultam
Oppolzer, Wolfgang,Walther, Eric,Balado, Carlos Perez,De Brabander, Jef
, p. 809 - 812 (1997)
The group-selective aldolization/desymmetrization of meso dialdehyde 5 with a borylenolate derived from N-propionylbornanesultam ent-2 yields very efficiently lactols 6 with simultaneous generation of four stereogenic centers. Oxidation (6→7) followed by saponification of the sultam moiety (7→4) provided the Prelog-Djerassi lactonic acid 4 in a three step sequence in 61-71% overall yield.
A Synthesis of the (+/-)-Prelog-Djerassi Lactone
Pearson, Anthony J.,Lai, Yen-Shi
, p. 442 - 443 (1988)
cis-5-7-Dimethylcyclohepta-1,3-diene, which is readily available using organoiron chemistry, was converted to all cis-3,7-diacetoxy-4,6-dimethylcycloheptene (5), which was subjected to asymmetric enzymatic hydrolysis to give hydroxy acetate (6), and this compound was converted in four steps to the (+/-)-Prelog-Djerassi lactone having high optical purity.
Asymmetric hydroformylation-initiated tandem sequences for syntheses of (+)-patulolide C, (-)-pyrenophorol, (+)-decarestrictine L, and (+)-prelog djerassi lactone
Risi, Roberto M.,Maza, Andrew M.,Burke, Steven D.
, p. 204 - 216 (2016/09/09)
Four different Rh-catalyzed asymmetric hydroformylation (AHF) tandem reactions have been developed in the context of the total syntheses of (+)-patulolide C, (-)-pyrenophorol, (+)-decarestrictine L, and (+)-Prelog-Djerassi lactone. A total synthesis of (+)-patulolide C has been accomplished in three steps utilizing a Rh(I)-catalyzed Z-selective anti-Markovnikov hydroacetoxylation of a known alkyne to give a Z-enol acetate with excellent selectivity. An AHF/intramolecular Wittig olefination cascade was utilized to set the C4-hydroxyl stereochemistry, E-olefin geometry, and form the macrolactone. In addition, both (-)-pyrenophorol and (+)-decarestrictine L have been synthesized from the enantiomeric (4R)- and (4S)-4-(tert-butyldimethylsiloxy)-1-pentyne in five and four steps, respectively. These syntheses feature Ru(II)-catalyzed Z-selective anti-Markovnikov hydroacetoxylation of terminal alkynes followed by AHF/Wittig olefination sequences to rapidly establish functionality and stereogenicity. A synthesis of (+)-Prelog-Djerassi lactone was accomplished in three isolations from the known 1-vinyl-4-methyl-2,6,7-trioxabicyclo[2.2.2]-octane ortho ester. An AHF/crotylation tandem sequence has been developed to set the C2-C4 stereochemistry. An asymmetric hydrogenation was employed to set the C6 stereochemistry, resulting in an especially efficient enantioselective synthesis from achiral starting material. In summary, these syntheses have greatly improved efficiency in terms of atom-economy, catalytic stereoselective transformations, inexpensive reagents, step-counts, and overall yield when compared with previous synthetic attempts.
A synthesis of (+)-prelog-djerassi lactonic acid
Hiscock, Steven D.,Hitchcock, Peter B.,Parsons, Philip J.
, p. 11567 - 11580 (2007/10/03)
A new approach to the synthesis of Prelog-Djerassi Lactonic acid (1) is reported. A key step in this synthesis involves an Ireland-Claisen rearrangement/silicon-mediated fragmentation sequence to provide the carbon framework in (1).
Stereocontrol in organic synthesis using silicon-containing compounds. A synthesis of the (±)-Prelog-Djerassi lactone
Chow, Hak-Fun,Fleming, Ian
, p. 2651 - 2662 (2007/10/03)
Each of the relative stereochemical relationships present in the Prelog-Djerassi lactone 34 was set up by a stereocontrolled reaction based on the presence of a silyl group. These were the enolate protonation 3→4 of a β-silyl ester, the enolate alkylation 11→12 of a β-silyl ester, silyl-to-hydroxy conversion with retention of configuration 13→14, and stereospecifically anti protodesilylation of the allylsilanes 26 and 27 giving largely the alkene 28. These allylsilanes had themselves been prepared in a stereocontrolled, convergent synthesis from the allylic acetates 24 and 25, providing thereby a general solution to the controlled synthesis of a new stereogenic centre relative to a resident centre without regard to their distance apart, except insofar as it influences a necessary separation of diastereoisomers (18 and 19 in this case). Using the opposite double bond geometries, the allylic acetates 29 and 30 gave the complementary pair of allylsilanes 31 and 32, which underwent stereospecifically anti protodesilylation to give largely the alkene 33 diastereoisomeric to 28 at C-6. The alkenes 28 and 33 were converted into the Prelog-Djerassi lactonic acid 34 and its C-6 epimer 35, respectively.
Synthesis of the Prelog-Djerassi Lactone and Protomycinolide IV Based on the Stereospecific Methylation of γ,δ-Epoxy Acrylates by Trimethylaluminum
Miyashita, Masaaki,Hoshino, Masahide,Yoshikoshi, Akira,Kawamine, Katsumi,Yoshihara, Kousei,Irie, Hiroshi
, p. 1101 - 1104 (2007/10/02)
The Prelog-Djerassi lactone, a key intermediate for the synthesis of several medicinally important macrolide antibiotics, and protomycinolide IV, a 16-membered macrolide, have been synthesized by employing the recently developed stereospecific methylation of γ,δ-epoxy acrylates by trimethylaluminum as key steps.
Unprecedented Stability of δ-Lactones with Axial Substituents rather than Equatorial ones; Comparison with the Prelog-Djerassi Lactone Derivative
Morimoto, Yoshiki,Mikami, Atsushi,Shirahama, Haruhisa
, p. 1376 - 1378 (2007/10/02)
A 1:1 mixture of the trisubstituted δ-lactones 11a and 11b was subjected to thermodynamically equilibrated conditions to give predominantly 11b with axial substituents rather than 11a with all equatorial ones, in contrast to the Prelog-Djerassi lactone derivatives 3a and 3b, and, further surprisingly, it has been found that the disubstituted lactone 10 also adopts a chair conformation with axial substituents.
Rection of Enohexopyranoside Acetates with Lithium Dimethylcuprate(I) and Its Application to Synthesis of Prelog-Djerassi Lactone
Kawauchi, Nobuya,Hashimoto, Hironobu
, p. 1441 - 1448 (2007/10/02)
In the reaction of two 2-O-acetyl-3-enohexopyranosides and four 4-O-acetyl-2-enohexopyranosides including 2-C-methyl and 4-C methyl derivatives, respectively, with lithium dimethylcuprate(I), anti SN2' substitution was proved to be preferential, giving the corresponding C-methylated derivatives.On the other hand, SN2 substitution occurred in the reaction of the 2-enopyranoside without methyl branch and D-glucal triacetate
WITTIG REARRANGEMENT-BASED APPROACHES TO STEREOCONTROL OVER THREE CONTIGUOUS CHIRAL CENTERS. NEW ENTRIES TO THE (+/-)-PRELOG-DJERASSI LACTONE
Nakai, Ei-ichi,Kitahara, Ei-ichiro,Sayo, Noboru,Ueno, Yoshio,Nakai, Takeshi
, p. 1725 - 1728 (2007/10/02)
Three Wittig-based approaches for stereocontrol over three contiguous chiral centers are described within the synthesis of the title lactone.In these methods, the erythro-selective Wittig variants are combined with one of the stereoselective processes: the Michael addition, the radical cyclization, and the hydroboration.
