94233-74-6Relevant academic research and scientific papers
Preparation of enantiomerically enriched α-alkoxystannanes by regioselective acetal exchange or acetal hydrolysis
Linderman, Russell J.,Cusack, Kevin P.,Jaber, Mohamad R.
, p. 6649 - 6652 (1996)
α-Alkoxyorganostannanes can be resolved via the methoxymenthyl ethers with subsequent regioselective acetal exchange or cleavage of the acetal group to the α-hydroxyalkylstannane.
Total Synthesis and Stereochemical Revision of Stereocalpin A: Mirror-Image Approach for Stereochemical Assignments of the Peptide-Polyketide Macrocycle
Kaneda, Masato,Inuki, Shinsuke,Ohno, Hiroaki,Oishi, Shinya
, p. 3047 - 3060 (2018/03/25)
Stereocalpin A is a cyclic depsipeptide with cytotoxic activity isolated from the Antarctic lichen Stereocaulon alpinum. Although a number of synthetic investigations of the unprecedented 12-membered macrocycle of stereocalpin A with a dipeptide segment and a polyketide substructure have been conducted, the configurational assignment has not been completed. In this study, we achieved the first total synthesis and stereochemical revision of stereocalpin A. To facilitate the comprehensive assessment of eight possible stereocalpin A isomers, four stereoisomers of polyketide precursors were conjugated with l-Phe-l-MePhe and d-Phe-d-MePhe dipeptides (MePhe: N-methylphenylalanine) to provide four possible isomers and four mirror-image structures of the remaining isomers, respectively. The comparative NMR analysis of a series of stereoisomers revealed that stereocalpin A possesses 2R,4S,5R-configurations, which is unique among the related 12-membered hybrid peptide-polyketide natural products reported recently. The NOE correlations in the polyketide substructure of stereocalpin A were also retrospectively analyzed among the eight possible stereoisomers.
Studies toward a total synthesis of rhizoxin d: Stereoselective preparation of the C11-C19 fragment
Padakanti, Srinivas,KiranKumar, Chetlur,Ashok, Ettam,Das, Parthasarathi
experimental part, p. 2709 - 2714 (2010/01/21)
The C11-C19 fragment of rhizoxin D was synthesized efficiently and stereoselectively. Stereoselective induction at C13 was achieved by means of the Crimmins protocol, whereas a substrate-controlled lithium aldol reaction gave the desired selectivity at th
A cross-metathesis approach to the synthesis of key precursor of the macrolide core of rhizoxin D
Padakanti, Srinivas,Sreekanth, Bukkapattanam R.,Mahendar, Velisoju,Pal, Manojit,Mukkanti, Khagga,Iqbal, Javed,Das, Parthasarathi
scheme or table, p. 2417 - 2420 (2009/04/08)
The synthesis of key precursor 5 of the macrolide core of rhizoxin D has been achieved by cross metathesis between two olefinic fragments 6 and 7. Both the olefinic fragments are easily synthesized in a diastereoselective manner from the common precursor
Studies on the synthesis of bitungolides A-E: Synthesis of the C(1-C(12) fragment
Xu, Yanfen,Huo, Xing,Li, Xinyun,Zheng, Huaiji,She, Xuegong,Pan, Xinfu
scheme or table, p. 1665 - 1668 (2009/04/10)
Synthesis of the core segment of bitungolides A-E has been achieved in 17 steps and 4.7% overall yield. Six stereogenic centers of bitungolides A-E were established via allylation, dihydroxylation, Myers alkylation, and Evans aldol reaction Thieme Stuttgart.
Synthetic studies on a marine natural product, palmerolide A: Synthesis of C1-C9 and C15-C21 fragments
Kaliappan, Krishna P.,Gowrisankar, Parthasarathy
, p. 1537 - 1540 (2008/02/05)
An efficient cross metathesis and Pd-catalyzed allylic rearrangement have been successfully used to construct the northern hemisphere of a cytotoxic marine natural product, palmerolide A. Georg Thieme Verlag Stuttgart.
Stereoselective synthesis of the C1-C10 fragment of rhizoxin D
Padakanti, Srinivas,Pal, Manojit,Mukkanti,Iqbal, Javed
, p. 5969 - 5971 (2007/10/03)
A novel approach towards the synthesis of the C1-C10 fragment of the biologically active antimitotic agent rhizoxin D is described. The synthesis involves a stereoselective Michael addition reaction of lithium diallyl cuprate with an α,β-unsaturated six m
Total synthesis of the potent microtubule-stabilizing agent (+)-discodermolide
Harried, Scott S.,Lee, Christopher P.,Yang,Lee, Tony I. H.,Myles, David C.
, p. 6646 - 6660 (2007/10/03)
The total synthesis of the potent microtubule-stabilizing, antimitotic agent (+)-discodermolide is described. The convergent synthetic strategy takes advantage of the diastereoselective alkylation of a ketone enolate to establish the key C15-C16 bond. The synthesis is amenable to preparation of gram-scale quantities of (+)-discodermolide and analogues.
Total synthesis of rhizoxin D, a potent antimitotic agent from the fungus Rhizopus chinensis
White, James D.,Blakemore, Paul R.,Green, Neal J.,Hauser, E. Bryan,Holoboski, Mark A.,Keown, Linda E.,Nylund Kolz, Christine S.,Phillips, Barton W.
, p. 7750 - 7760 (2007/10/03)
Rhizoxin D (2) was synthesized from four subunits, A, B, C, and D representing C3-C9, C10-C13, C14-C19, and C20-C27, respectively. Subunit A was prepared by cyclization of iodo acetal 21, which set the configuration at C5 of 2 through a stereoselective addition of the radical derived from dehalogenation of 21 at the β carbon of the (Z)-α,β-unsaturated ester. Aldehyde 29 was obtained from phenylthioacetal 24 and condensed with phosphorane 30, representing subunit B, in a Wittig reaction that gave the (E,E)-dienoate 31. This ester was converted to aldehyde 33 in preparation for coupling with subunit C. The latter in the form of methyl ketone 55 was obtained in six steps from propargyl alcohol. An aldol reaction of 33 with the enolate of 55 prepared with (+)-DIPCl gave the desired β-hydroxy ketone 56 bearing a (13S)-configuration in a 17-20:1 ratio with its (13R)-diastereomer. After reduction to anti diol 57 and selective protection as TIPS ether 58, the C15 hydroxyl was esterified to give phosphonate 59. An intramolecular Wadsworth-Emmons reaction of aldehyde 62, derived from δ-lactone 60, furnished macrolactone 63, which was coupled in a Stille reaction with stannane 68 to give 2 after cleavage of the TIPS ether.
Synthetic studies toward ansatrienines: Application of the Evans- Tishchenko reaction to chiral enones
Schoening, Kai-Uwe,Hayashi,Powell, Douglas R.,Kirschning, Andreas
, p. 817 - 820 (2007/10/03)
Practical syntheses of the C9-C14 sterotriade 5 and the C1-C8 polyene unit 6 in ansatrienine A (mycotriene) (1a), and other ansamycin antibiotics is described. A key step for controlling the configuration of the stereogenic center at C13 involves the stereoselective reduction of enone 10 using the Evans-Tishchenko reaction.
