Sharpless asymmetric dihydroxylation (also called the Sharpless bishydroxylation) is the chemical reaction of an alkene with osmium tetroxide in the presence of a chiral quinine ligand to form a vicinal diol.The reaction has been applied to alkenes of virtually … Soc.. 1988, 110, 1968. Syn hydroxylation of alkenes or Syn dihydroxylation of alkenes using osmium tetroxide OsO4 and potassium permanganate KMnO4 is discussed here with detailed mechanism. Band 94, Nr. The Sharpless Dihydroxylation or Bishydroxylation is used in the enantioselective preparation of 1,2-diols from prochiral olefins.

8, 1994, S. 2483–2547, doi:10.1021/cr00032a009. The Journal of Organic Chemistry 2011, 76 (20) , 8554-8559.

Catalytic Cycle: Turnover is achieved by reoxidation with stoichiometric oxidants: General References ・Hentges, S. G.; Sharpless, K. B. J. Asymmetric dihydroxylation of olefins is a core transformation in organic chemistry and its syn-selective version is commonly catalysed by toxic osmium catalysts. Mechanism of the Sharpless Asymmetric Dihydroxylation. The desired key intermediates aldehyde (12), iodo alkene (11) and epoxy (10) were also made following the same reported protocol except that TBDPS rather than TBS was used for improved reaction monitoring using TLC. J. 430 When conjugated alkenes were treated with nitrogen-containing reagents in the presence of (DHQ) 2 PHAL (see Section 6.5.2.2), using what is effectively the AD-mix-α, 394 chiral, nonracemic amino alcohols were formed. Sharpless asymmetric dihydroxylation is applicable also for α,β-unsaturated carbonyl compounds (Scheme 10). DOI: 10.1021/jo2016746. Sharpless Aminohydroxylation Sharpless Oxyamination. The catalytic asymmetric dihydroxylation of several allyl 2‐O ‐benzyl‐α‐ D ‐xylosides with AD‐mix β and PYR(DHQD) 2 shows almost no diastereofacial selectivity if the 3‐ and 4‐OH groups are unprotected or acetylated. Our synthesis of the CDE ring fragment of pectenotoxin-4 utilised two key steps to make the complex bicyclic ketal unit: (i) a rhodium-catalysed vinyl group 1,4-addition as the major C–C bond forming step; (ii) a stereoselective Sharpless Asymmetric Dihydroxylation (SAD) of the resulting 1,1-disubstituted ho Asymmetric Dihydroxylation (AD) Reaction Scheme: The Asymmetric Dihydroxylation involves the conversion of a substituted alkene to a diol. Die Sharpless-Epoxidierung ist eine Namensreaktion in der organischen Synthese-Chemie.Sie gehört zur Gruppe der katalytisch asymmetrischen Reaktionen.Ausgehend von prochiralen Verbindungen kann selektiv nur ein Enantiomer des Produktes gebildet werden; es handelt sich um eine enantio- und diastereoselektive Reaktion.Die Reaktion liefert 2,3-Epoxyalkohole aus Allylalkoholen.

Sharpless, Syntheses of Diols by Catalytic Dihydroxylation Soc.

Asymmetric dihydroxylation of alkenes can be modified to synthesize chiral amino alcohols, 429 in what is known as Sharpless asymmetric aminohydroxylation (or oxyamination). Ii … Original publication: J. A Sharpless asymmetric dihydroxylation (Kolb et al., 1994) produced the diol intermediate (1) in 82% yield in a single step . Sharpless asymmetric dihydroxylation has also seen use as a method for kinetic resolution.

Enantioselectivity is achieved through the addition of dihydroquinine- and dihydroquinidine-derived chiral ligands. In: Chemical Reviews. M. Beller and K.B. Chem.

1942, 550, 99-133.) The Sharpless asymmetric dihydroxylation was developed by K. Barry Sharpless to use catalytic amounts of OsO 4 along with the stoichiometric oxidant K 3 [Fe(CN) 6]. Sharpless asymmetric dihydroxylation (also called the Sharpless bishydroxylation) is the chemical reaction of an alkene with osmium tetroxide in the presence of a chiral quinine ligand to form a vicinal diol.The reaction has been applied to alkenes of virtually … 1980, 102, 4263. Am.

Am.