410095-15-7Relevant academic research and scientific papers
Stereoselective synthesis of the C13-C28 subunit of (-)-laulimalide utilizing an α-chlorosulfide intermediate
Raghavan, Sadagopan,Samanta, Pradip Kumar
, p. 1983 - 1987 (2013/09/24)
A stereoselective route to the C13-C28 subunit of (-)-laulimalide is described. l-Tartaric acid is the source of the hydroxy groups at C19 and C20. An α-chlorosulfide is employed as the key intermediate for the creation of the C17-C18 bond and the C16-C17 double bond was introduced using the Mislow-Braverman rearrangement and Hutchin's dexoxygenation with concomitant double bond transposition reaction. The C15 and C23 stereogenic centers were created using catalytic asymmetric reactions. The trisubstituted and trans-disubstituted alkenes were created stereoselectively by taking advantage of ring-closing metathesis and the Julia-Kocienski olefination reaction, respectively. Georg Thieme Verlag Stuttgart, New York.
Total synthesis of laulimalide: Synthesis of the northern and southern fragments
Trost, Barry M.,Seganish, W. Michael,Chung, Cheol K.,Amans, Dominique
, p. 2948 - 2960 (2012/04/23)
The first stage in the development of a synthetic route for the total synthesis of laulimalide (1) is described. Our retrosynthetic analysis envisioned a novel macrocyclization route to the natural product by using a Ru-catalyzed alkene-alkyne coupling. This would be preceded by an esterification of the C19 hydroxyl group, joining together two equally sized synthons, the northern fragment 7 and the southern fragment 8. Our first generation approach to the northern fragment entailed a key sequential Ru/Pd coupling sequence to assemble the dihydropyran. The key reactions proceeded smoothly, but the inability to achieve a key olefin migration led to the development of an alternative route based on an asymmetric dinuclear Zn-catalyzed aldol reaction of a hydroxyl acylpyrrole. This key reaction led to the desired diol adduct 66 with excellent syn/anti selectivity (10:1), and allowed for the successful completion of the northern fragment 7. The key step for the synthesis of the southern fragment was a chemoselective Rh-catalyzed cycloisomerization reaction to form the dihydropyran ring from a diyne precursor. This reaction proved to be selective for the formation of a six-membered ring, over a seven. The use of an electron-deficient bidentate phosphine allowed for the reaction to proceed with a reduced catalyst loading. Making the pieces: The synthesis of two equal-sized fragments of laulimalide is described (see scheme). A key Rh-catalyzed cycloisomerization reaction allowed for an efficient synthesis of the endocyclic dihydropyran and a stereoselective acylpyrrole Zn-aldol reaction allowed for the formation of the syn-diol. Copyright
Evaluating transition-metal-catalyzed transformations for the synthesis of laulimalide
Trost, Barry M.,Amans, Dominique,Seganish, W. Michael,Chung, Cheol K.
supporting information; experimental part, p. 17087 - 17089 (2010/03/23)
(Chemical Equation Presented) Laulimalide is a structurally unique 20-membered marine macrolide displaying microtubule stabilizing activity similar to that of paclitaxel and the epothilones. The use of atom-economical transformations such as a Rh-catalyze
An improved synthesis of the C15-C28 fragment of laulimalide
Sivaramakrishnan,Nadolski, Geoffry T.,McAlexander, Ian A.,Davidson, Bradley S.
, p. 213 - 216 (2007/10/03)
The C15-C28 fragment of the paclitaxel-like antimicrotubule agent laulimalide has been synthesized in 12 linear steps from known epoxide 5, with an overall yield of 16%. The methyldihydropyran ring of the side chain was efficiently prepared using ring-closing olefin metathesis chemistry. The 19,20-diol stereochemistry originates in starting material 7 and the side chain was appended using a Kocienski-modified Julia coupling.
