- An asymmetric dihydroxylation route to (S)-oxybutynin
-
An asymmetric synthesis of (S)-oxybutynin 1 is described using the Sharpless asymmetric dihydroxylation of α-cyclohexylstyrene as the key step.
- Gupta, Priti,Fernandes, Rodney A.,Kumar, Pradeep
-
-
Read Online
- Syn-dihydroxylation of alkenes using a sterically demanding cyclic diacyl peroxide
-
The syn-dihydroxylation of alkenes is a highly valuable reaction in organic synthesis. Cyclic acyl peroxides (CAPs) have emerged recently as promising candidates to replace the commonly employed toxic metals for this purpose. Here, we demonstrate that the structurally demanding cyclic peroxide spiro[bicyclo[2.2.1]heptane-2,4′-[1,2]dioxolane]-3′,5′-dione (P4) can be effectively used for the syn-dihydroxylation of alkenes. Reagent P4 also shows an improved selectivity for dihydroxylation of alkenes bearing β-hydrogens as compared to other CAPs, where both diol and allyl alcohol products compete with each other. Furthermore, the use of enantiopure P4 (labeled P4′) demonstrates the potential of P4′ for a metal-free asymmetric syn-dihydroxylation of alkenes.
- Pilevar, Afsaneh,Hosseini, Abolfazl,Becker, Jonathan,Schreiner, Peter R.
-
p. 12377 - 12386
(2019/10/11)
-
- Visible light-promoted dihydroxylation of styrenes with water and dioxygen
-
An efficient visible light promoted metal-free dihydroxylation of styrenes with water and dioxygen has been developed for the construction of vicinal alcohols. The protocol was operationally simple with a broad substrate scope. The mechanistic studies demonstrated that one of the hydroxyl groups came from water and the other one came from molecular oxygen. Additionally, the β-alkyoxy alcohols could also be obtained using a similar strategy.
- Yang, Bo,Lu, Zhan
-
p. 12634 - 12637
(2017/12/02)
-
- Process for the synthesis of enantiomerically pure cyclohexylphenyl glycolic acid
-
The present invention provides a process for the synthesis of enantiomerically pure cyclohexylphenyl glycolic acid of formula (1). The present invention more particularly relates to a process using cyclohexylphenyl ketone for the synthesis of enantiomeric
- -
-
-
- Syntheses of (S)-(+)-trihexyphenidyl hydrochloride and (S)-(+)-procyclidine hydrochloride, two anticholinergics, using (S)-(-)-3-cyclohexyl-3-hydroxy-3-phenylpropanoic acid as chiral synthon.
-
The absolute configuration of the more active (-)-enantiomer of the anticholinergic trihexyphenidyl hydrochloride has been established as (R) by syntheses of (S)-(+)-procyclidine hydrochloride, whose absolute configuration has been established previously,
- Schjelderup,Harbitz,Groth,Aasen
-
p. 356 - 361
(2007/10/02)
-
- Dedoublement et determination de la configuration absolue des enantiomeres de l'acide (thienyl-3)-2 cyclohexyl-2 hydroxy-2 acetique. Application a la synthese d'esters anticholinergiques du quinuclidinol-3
-
Enantiomeric 2-(3-thienyl)-2-cyclohexyl-2-hydroxy acetic acids 1 were obtained by the resolution of (+/-)-1 using (+)- and (-)-ephedrine as the resolving agents, and by asymmetric synthesis; (+)-1 was assigned S absolute configuration (i) by comparing the circular dichroism spectra of a series of derivatives of 1 with those of the corresponding derivatives of S-(+)-2-phenyl-2-cyclohexyl-2-hydroxy acetic acid 1', and (ii) by application of the quasi-racemate method.On transesterification of the methyl esters of 1, R-(+)-2 and S-(-)-2, with R-(-)- or S-(+)-1-azabicyclo-3-octanol (or 3-quinuclidinol), the four diastereoisomers of 3-quinuclidinyl 2-(3-thienyl)-2-cyclohexyl-2-hydroxy-acetate were obtained, i.e., (+)-2R, 3'S-6, (-)-2S, 3'R-6, (+)-2R, 3'R-7, and (-)-2S, 3'S-7.These compounds exhibited anticholinergic activity.
- Tambute, Andre,Collet, Andre
-
-