Asymmetric functionalisation of prochiral 1,3-diols based on an efficient 1,6-chiral induction: the diastereoselective C–O bond fission in chiral β-arylsulfinyl acetal via two types of chelation control
The novelasymmetric functionalisation of a prochiral 1,3-diol is accomplished by the diastereoselective C–O bond fission of the chiral β-arylsulfinyl acetalvia two types of chelation controlled transition states (A and C in Scheme 4).
Asymmetric Desymmetrization of Prochiral 1,3-Diols via Diastereoselective C-O Bond Fission of Bicyclic Acetal Using a Chiral Sulfoxide as a Chiral Auxiliary.
Asymmetric desymmetrization of a prochiral 1, 3-diol was established by diastereoselective C-O bond fission of the chiral α-sulfinyl acetal 6. Treatment of 6 with titanium tetrachloride afforded mainly 7a via an oxonium intermediate, while with lithium diisopropylamide 7b was selectively obtained via diastereoselective β-elimination followed by an olefin isomerization.
A series of asymmetrized bis(hydroxymethyl)propanoates (BHYMP*) has been prepared in both enantiomeric forms through a chemoenzymatic methodology involving complementary diacetate monohydrolyses and diol monoacetylations catalyzed by lipases. (C) 1997 Elsevier Science Ltd. All rights reserved.
Bifunctional chiral synthons via biochemical methods, 4. Chiral precursors to (+)-biotin and (−)-a-factor.