945-06-2Relevant articles and documents
A Stereoselective Total Synthesis of the Prelog-Djerassi Lactone
Bartlett, Paul A.,Adams, Jerry L.
, p. 337 - 342 (1980)
A total synthesis of racemic Prelog-Djerassi lactone (1) has been achieved using the mercuric ion induced cyclization of aldehyde acid 12a to control the stereochemistry at C-2 and C-3.Demercuration of the product (14a) is selectively accomplished with sodium trithiocarbonate in methanol at -60 deg C, affording the Prelog-Djerassi lactone (1) and the 2-epi isomer 17 in 3.5:1 ratio after hydrolysis and oxidation.Demercuration with sodium borohydride, hydrolysis, and oxidation result in the 2-epi compound 17 almost exclusively.
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.
A SYNTHESIS OF THE PRELOG-DJERASSI LACTONE USING OPEN-CHAIN STEREOCONTROL BASED ON ALLYLSILANE CHEMISTRY
Chow, Hak-Fun,Fleming, Ian
, p. 397 - 400 (2007/10/02)
A stereocontrolled synthesis of the Prelog-Djerassi lactone (28) is described; all the stereocontrol sterms from the high diastereoselectivity of electrophilic attack on a double bond adjacent to a chiral centre carrying a silyl group.
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.
TOTAL SYNTHESIS OF PROTOMYCINOLIDE IV
Honda, Masanori,Katsuki, Tsutomu,Yamaguchi, Masaru
, p. 3857 - 3860 (2007/10/02)
A 16-membered macrolide antibiotic, protomycinolide IV, was synthesized from two fragments to which the chirality was introduced by asymmetric epoxidation of the appropriately chosen allylic alcohols.A new synthesis of the Prelog-Djerassi lactonic acid from one of the intermediates of the synthesis was also carried out.
1,2 ASYMMETRIC INDUCTION IN THE CYCLIC HYDROBORATION OF 1,5-DIENES. A SYNTHESIS OF THE PRELOG-DJERASSI LACTONE
Morgans, David J.
, p. 3721 - 3724 (2007/10/02)
Cyclic hydroboration of an appropriately substituted 1,5-diene yields a 1,5 diol as the major product which can be converted to the racemic Prelog-Djerassi lactone.
