447454-25-3Relevant academic research and scientific papers
Gold(I)-catalysed intramolecular hydroamination of α-quaternary alkynes: Synthetic studies towards spiroimine marine toxins
Zhang, Yanchuan C.,Furkert, Daniel P.,Guéret, Stéphanie M.,Lombard, Fanny,Brimble, Margaret A.
, p. 4896 - 4898 (2011/10/05)
Cyclic spiroimines form an essential component of the bioactive pharmacophore in a number of potent fast-acting marine biotoxins, including the pinnatoxins, gymnodimine and the spirolides. These present a significant challenge for the total synthesis of this class of natural products. A novel approach to these cyclic spiroimines based on metal-catalysed hydroamination of spiroaminoalkyne precursors is reported herein. Au(PPh3)SbF 6 was found to effect the formation of bench-stable 5,6- and 6,6-spiroimine systems in high yields, although the 7,6-analogue remained elusive. To the best of our knowledge these are the first reported examples of α-quaternary cyclic imines formed via alkyne hydroamination.
Synthesis of enantiopure bicyclic α,α-disubstituted spirolactams via asymmetric Birch reductive alkylation
Gueret, Stephanie M.,O'connor, Patrick D.,Brimble, Margaret A.
supporting information; experimental part, p. 963 - 966 (2009/07/11)
The synthesis of enantiopure bicyclic α,α-disubstituted spirolactams is described using a diastereoselective Birch reductive alkylation as the key step. Hydrogenation of the resultant alkylated cyclohexadienes followed by intramolecular cyclization provides access to enantiopure 8-azaspiro[5.6]dodecan-7-ones.
Total synthesis of salicylihalamides A and B
Herb, Christian,Bayer, Alexander,Maier, Martin E.
, p. 5649 - 5660 (2007/10/03)
The paper illustrates two efficient routes to macrolactone 19 containing a 3-(para-methoxybenzyloxy)propyl side chain at C-15. The chiral center at C-15 was introduced by a Noyori reduction of keto ester 5. The intermediate common to both routes, aldehyde 8, was prepared from keto ester 5. The subsequent chain extension utilized Evans aldol reactions. The first route leads to the alkene 14, which was used, after hydroboration, for a Suzuki cross-coupling reaction with vinyl iodide 15. The derived seco acid 18 was converted into the macrolactone 19 by a Mitsunobu lactonization by using immobilized triphenylphosphine. Alternatively, an aldol reaction of 8 with the 4-pentenoyl derivative 20 was used to prepare alkene 26. This building block led to ester 28, which could also be converted into macrolactone 19 by the classical ring-closing metathesis. After conversion of the C-15 side chain to the corresponding aldehyde, the enamide was introduced through hemiaminal formation and formal elimination of water. Separation of the double-bond isomers and removal of the silyl protecting groups provided salicylihalamides A (E)-1 and B (Z)-1.
Photoaffinity analogues of farnesyl pyrophosphate transferable by protein farnesyl transferase
Chehade, Kareem A. H.,Kiegiel, Katarzyna,Isaacs, Richard J.,Pickett, Jennifer S.,Bowers, Katherine E.,Fierke, Carol A.,Andres, Douglas A.,Spielmann, H. Peter
, p. 8206 - 8219 (2007/10/03)
Farnesylation is a posttranslational lipid modification in which a 15-carbon farnesyl isoprenoid is linked via a thioether bond to specific cysteine residues of proteins in a reaction catalyzed by protein farnesyltransferase (FTase). We synthesized analogues (3-6) of farnesyl pyrophosphate (FPP) to probe the range of modifications possible to the FPP skeleton which allow for efficient transfer by FTase. Photoaffinity analogues of FPP (5, 6) were prepared by substituting perfluorophenyl azide functional groups for the ω-terminal isoprene of FPP. Substituted anilines replace the ω-terminal isoprene in analogues 3 and 4. Compounds 3-5 were prepared by reductive amination of the appropriate anilines with 8-oxogeranyl acetate, followed by ester hydrolysis, chlorination, and pyrophosphorylation. Additional substitution of three methylenes for the β-isoprene of FPP gave photoprobe 6 in nine steps. Preparation of the analogues required TiCl4-mediated imine formation prior to NaBH(OAc)3 reduction for anilines with a pKa 3PCl2 conversion of allylic alcohols 13-16 into corresponding chlorides 17-20. Analogues 3-6 are efficiently transferred to target N- dansyl-GCVLS peptide substrate by mammalian FTase. Comparison of analogue structures and kinetics of transfer to those of FPP reveals that ring fluorination and para substituents have little effect on the affinity of the analogue pyrophosphate for FTase and its transfer efficiency. These results are also supported with models of the analogue binding modes in the active site of FTase. The transferable azide photoprobe 5 photoinactivates FTase. Transferable analogues 5 and 6 allow the formation of appropriately posttranslationally modified photoreactive peptide probes of isoprene function.
