| 1. |
- Blid, Jan, et al.
(author)
-
Lewis acid mediated asymmetric 2,3 -sigmatropic rearrangement of allylic amines. Scope and mechanistic investigation
- 2007
-
In: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 72:4, s. 1294-1300
-
Journal article (peer-reviewed)abstract
- [GRAPHIC] The first asymmetric [2,3]-sigmatropic rearrangement of achiral allylic amines has been realized by quaternization of the amines with an enantiomerically pure diazaborolidine and subsequent treatment with Et3N. The resultant homoallylic amines were obtained in good yields and excellent ee's. The observed diastereo- and enantioselectivities were rationalized by invoking a kinetically controlled process, and support for this model was obtained from an NMR spectroscopic investigation of the chiral Lewis acid-substrate complex. The structure of the Lewis acid-product complex was established by X-ray crystallographic analysis and supported the proposed mechanism.
|
|
| 2. |
- Borg, Tessie, et al.
(author)
-
Lewis Acid-Promoted Addition of 1,3-Bis(silyl)propenes to Aldehydes : A Route to 1,3-Dienes
- 2011
-
In: Journal of Organic Chemistry. - : American Chemical Society (ACS). - 0022-3263 .- 1520-6904. ; 76:19, s. 8070-8075
-
Journal article (peer-reviewed)abstract
- The Lewis acid-promoted addition of 1,3-bis(silyl)-propenes to aldehydes to provide the corresponding (E)-1,3-dienes in excellent stereoselectivity and good to excellent yields is reported. The procedure is mild, base-free, and operationally straightforward.
|
|
| 3. |
|
|
| 4. |
- Tuzina, Pavel, et al.
(author)
-
Asymmetric Lewis Acid Mediated 1,2 -Rearrangement of Proline-Derived Ammonium Ylides
- 2009
-
In: Organic Letters. - : American Chemical Society (ACS). - 1523-7060 .- 1523-7052. ; 11:4, s. 919-921
-
Journal article (peer-reviewed)abstract
- The first example of asymmetric Lewis acid mediated [1,2]-rearrangement of N-benzylic proline amides to form quaternary proline derivatives is reported. The presented reaction is shown to proceed with remarkable high C-N-C chirality transfer. Various quaternary proline derivatives have been prepared in good to excellent yields and high enantiomeric purity.
|
|
| 5. |
- Tuzina, Pavel, 1980-
(author)
-
Development of New Methodology in Organic Synthesis: Lewis Acid-Mediated Rearrangements of Ammonium Ylides and Addition of 1, 3-bis(silyl) propenes to Aldehydes
- 2009
-
Doctoral thesis (other academic/artistic)abstract
- This thesis deals with the development of new methodologies in organicsynthesis. The main focus is on the development of Lewis acid-mediated [1,2]-rearrangements of ammonium ylides and the novel addition of 1,3-bis(silyl)propenes to carbonyl compounds.The first part of this thesis describes the development of a Lewis acidmediated[1,2]-Stevens rearrangement of various glycine derivatives. Thismethodology was then applied to the development of an asymmetric Lewis acid mediated [1,2]-Stevens rearrangement of cyclic ammonium ylides. There markably high degree of C→N→C chirality transfer is described. In addition, this methodology was successfully applied to the synthesis of various quaternary proline derivatives in enantiomerically pure form.Secondly, a brief study of the asymmetric [2,3]-rearrangement of α-substitutedglycine derivatives is presented. The investigation revealed a severely limitedreaction scope. The subsequent study on developing super-reactive cationicLewis acid also met with little success.Finally, an addition reaction of various 1,3-bis(silyl)propenes to glyoxalates has been developed. The reaction products correspond to the direct vinylation ofglyoxalates. The corresponding highly functionalized δ-hydroxy allylsilanes were obtained in high yields.
|
|
| 6. |
- Tuzina, Pavel, et al.
(author)
-
Lewis acid mediated 1,2 -rearrangement of ammonium ylides
- 2007
-
In: Tetrahedron Letters. - : Elsevier BV. - 0040-4039 .- 1359-8562. ; 48:28, s. 4947-4949
-
Journal article (peer-reviewed)abstract
- The first example of Lewis acid mediated [1,2]-rearrangement of various glycine derivatives has been developed. A brief study of steric and electronic properties of the migrating group is presented. The corresponding amides were obtained in good yields and in the case of substrate 4d, moderate diastereoselectivity was observed.
|
|
| 7. |
- Tuzina, Pavel, et al.
(author)
-
Lewis acid-promoted carbonyl addition of 1,3-bis(silyl)propenes
- 2008
-
In: Tetrahedron Letters. - : Elsevier BV. - 0040-4039 .- 1359-8562. ; 49:48, s. 6882-6884
-
Journal article (peer-reviewed)abstract
- A novel synthetic protocol for Lewis acid-promoted addition of 1,3-bis(silyl)propenes to N-phenyl glyoxylamide and ethyl glyoxylate is developed. The reaction does not appear to be influenced by the steric bulk of the 1,3-bis(silyl)propenes, and represents a new approach to vinylation of glyoxylates; the products are obtained in good yields.
|
|
| 8. |
- Tuzina, Pavel, et al.
(author)
-
N-Benzyl-1-(dimethylamino)-2-methyl-1-oxo-propan-2-aminium bromide
- 2006
-
In: Acta Crystallographica Section E. - : International Union of Crystallography (IUCr). - 1600-5368. ; 62, s. O2971-O2972
-
Journal article (peer-reviewed)abstract
- The title compound, C13H21N2O+.Br-, was crystallized from a CH2Cl2 solution of N-2, N-2-dibenzyl-N,N, 2-trimethylalaninamide and BBr3. The geometry of the cation is unexceptional. Intermolecular N-H (...) O and N-H (...) Br hydrogen bonds link two cations and two anions into a hydrogen-bonded cluster. The crystal packing is further stabilized by van der Waals forces.
|
|
