Chemical and Biological Synthesis of Chiral ..

114) Synthesis of (-)-Cubebol by IntramolecularCyclopropanation of a Terminal Epoxide' D. M. Hodgson and S. Salik,Synlett, 2009, 1730 (Thieme Chemistry Journal Awardee Article).

ChiPros Chiral Epoxides | Sigma-Aldrich

Design and Synthesis of ß-Methoxyacrylate Analogues via Click Chemistry and Biological Evaluations.

The dominant epoxides industrially are ..

We have developed a powerful method for the stereoselective synthesis of 1,4-diols through the copper-catalyzed borylation of allylic epoxides. The method allows for the synthesis of primary, secondary and tertiary diols, with syn or anti relative stereochemistry, in good yields and high diastereomeric ratios. Additionally, protection of the hydroxyl group prior to the C-B bond oxidation allows access to orthogonally protected 1,4-diols.

Chiral epoxides can often be derived ..

Spiroaminoborate ester 1 derived from diphenylprolinol was highly effective for the reduction of a variety of aryl, heteroaryl,, α-alkoxy and aliphatic ketones providing the desired secondary alcohols in excellent yield with excellent enantioselectivity, higher or similar to Corey’s OAB (CBS reagent). Presently, we are interested in the synthesis of nonracemic α-aryloxy- and α-amino alcohols as important chiral building blocks for the preparation of neurobiological active molecules. We, herein, describe a simple and convenient procedure for the preparation of optical active epoxides in high yield with excellent enantiopurity and their application to the synthesis of optically pure β-hydroxy ethers and 1,2-azido alcohols.

Bio- and chemo-catalytic preparations of chiral ..

66) Organolithium-Induced Synthesis of AcyclicUnsaturated Amino Alcohols from Epoxides of Dihydropyrroles andTetrahydropyridines' D. M. Hodgson, T. J. Miles and J. Witherington,Tetrahedron, 2003, 59, 9729. (Symposium in-Print: Oxiranyl and Aziridinyl Anions as Reactive Intermediates in Synthetic Organic Chemistry).

Consiga Chemical synthesis aqui

Optically active 2-azido-2-aryl ethanols are well-known precursor for the synthesis of a broad variety of enantiopure 1,2-amino alcohols, which are essential building blocks in the preparation of neurobiological active compounds., In addition, β-amino alcohols have been extensively used in asymmetric synthesis as chiral ligands, organic catalysts, and chiral auxiliaries or transfer agents. Recently, Qu and coworkers reported the preparation of racemic 1,2-diols and 1,2-azido alcohols by the ring-opening of epoxides in hot water. Due to the importance of nonracemic 1,2-amino alcohol, we were interested in studying the ring opening reaction of optically pure epoxides with NaN3. As indicated in , when styrene epoxide (7a) and sodium azide were heated in water at 60 °C for 3.5 h, 2-azido-2-phenyl ethanol 12a was formed as the main product with only trace amount of regioisomer 13a, as determined by GC-MS and 1H NMR analyses of the crude product. The ratio of 12a and 13a by GC-MS analysis was 95.4:4.6. After purification by preparative TLC, it was afforded (S)-12a in 91% yield and 99% ee, based on HPLC analysis on a chiral column. Since highly enantiopure (S)-1-phenyl-2-azido ethanol was obtained, and more significantly, with complete inversion of configuration, the reaction was carried out with the p-chlorostyrene oxide 7d to demonstrate the generality of this valuable ring opening reaction. According to the analysis by GC-MS, the ratio of 2-azido-arylethanol 12d to 13d was 93:7. Remarkably, 12d was isolated in excellent yield (88%) and its optical purity was 98% ee. The stereochemistry of these compounds was confirmed by full spectroscopic analysis and optical rotation. Interestingly, this transformation only slightly decreased the enantioselectivities of compounds 12a (99% ee) and 12d (98% ee), obtaining the 2-azido-1-arylethanols with inversion of configuration at the stereogenic center. Noteworthy, this highly regioselective and enantioselective conversion of styrene oxides to 1,2-azido alcohols was conducted under mild and environmental favorable conditions using only hot water, providing a rapid access to important non natural amino alcohols, as well as to biological building blocks that can be used for example in the click chemistry for the formation of chiral triazoles or amides. Further expansion of the azidolysis reaction of epoxides and reduction of the azido group to obtain a variety of 2-amino-2-heteroaryl ethanols will be addressed in future studies.

bio- and chemo-catalytic preparations of chiral epoxides …

Inspired by unsolved problems found in the total synthesis of complex molecules, we search for unconventional ways to activate boron compounds in an efficient way. We are especially interested in the formation of C-B bonds that are not possible using classical approaches. In doing so, we want to create a platform of novel boron containing molecules that could provide new areas of chemical space for biological screening and simultaneously be a toolbox for the preparation of valuable synthetic intermediates. Some examples our recent projects are described below.