- Stereocontrol by quaternary centres: A stereoselective synthesis of (-)-luminacin D
-
Very high diastereoselectivity can be achieved by 1,3-chelation-controlled allylation of aldehydes that possess a non-chelating α-ether substituent, even if the α-position is a quaternary centre and/or a spiro-epoxide. This reaction was used as a key step in an enantioselective synthesis of the angiogenesis inhibitor luminacin D.
- Bartlett, Nathan,Gross, Leona,Peron, Florent,Asby, Daniel J.,Selby, Matthew D.,Tavassoli, Ali,Linclau, Bruno
-
supporting information
p. 3306 - 3310
(2014/04/03)
-
- Stereoselective synthesis of substituted 5-hydroxy-1,3-dioxanes
-
A series of 5-hydroxy-1,3-dioxanes has been synthesized using a practical three-step strategy beginning with acetal/ketal formation of tris(hydroxymethyl)aminomethane followed by oxidative cleavage of the amino alcohol. After the ketone was revealed, stereoselective reduction with common hydride reagents, LiAlH4 for the trans isomers and L-Selectride for the cis analogues, gave the target compounds in high yield.
- Forbes, David C.,Ene, Doina G.,Doyle, Michael P.
-
p. 879 - 882
(2007/10/03)
-
- 1,3-Dioxan-5-ones: synthesis, deprotonation, and reactions of their lithium enolates
-
A general synthetic route to 2-alkyl- and 2,2-dialkyl-1,3-dioxan-5-ones, using tris(hydroxymethyl)nitromethane as the starting material, is described.Deprotonation of these compounds was studied.It was established that these dioxanones could be deprotonated with LDA; however, the reduction of the carbonyl group via a hydride transfer from LDA, giving the corresponding dioxanols, often competed with deprotonation.The reduction could be minimized by using Corey's internal quench procedure to form silyl enol ethers and was less pronounced in 2,2-dialkyldioxanones (ketals) than in 2-alkyldioxanones (acetals).Self-aldol products were observed when dioxanone lithium enolates were quenched with H2O.Addition reactions of lithium enolates of dioxanones to aldehydes were threo-selective as predicted by the Zimmerman-Traxler model.Dioxanones having two different alkyl groups at the 2-position were deprotonated enantioselectively by chiral lithium amide bases with enantiomeric excess (ee) of up to 70percent. - Key words: 1,3-dioxan-5-ones, enantioselective deprotonation, chiral lithium amides.
- Majewski, Marek,Gleave, D. Mark,Nowak, Pawel
-
p. 1616 - 1626
(2007/10/02)
-
- The total synthesis of antrimycin D(v); III: Construction of the protected hexapeptide and deprotection
-
In the preceding communication we described the synthesis of tetrahydropyridazine-3-carboxylic acids and their incorporation into peptides. We have also prepared the tripeptide 2 which is contained in the antibiotic antrimycin D(v) 15. We now report on th
- Schmidt,Riedl
-
p. 815 - 818
(2007/10/02)
-