Download PDF
Synthesis 2005(19): 3271-3278  
DOI: 10.1055/s-2005-918487
PAPER
© Georg Thieme Verlag Stuttgart · New York

1,3-Dipolar Cycloadditions to Unsymmetrical Ketone-Derived Chiral Stabilized Azomethine Ylides: Strategies for the Synthesis of Highly Substituted Amino Acids

David J. Aldousa, Michael G. B. Drewb, William N. Draffinb, Estelle M-N. Hamelinb, Laurence M. Harwood*b, Sukanthini Thurairatnama
a Rhône Poulenc Rhorer Limited, Rainham Road South, Dagenham, Essex RM10 7XS, UK
b School of Chemistry, University of Reading, Whiteknights, Reading, Berkshire, RG6 6AD, UK
Fax: +44(118)3786121; e-Mail: l.m.harwood@reading.ac.uk;
Further Information

Publication History

Received 14 September 2005
Publication Date:
14 November 2005 (online)

    Permissions and Reprints All articles of this category

Abstract

We report herein, the first generation of unsymmetrical ketone-derived chiral stabilized azomethine ylides. Intramolecular and intermolecular cycloaddition strategies have been utilized to synthesize both an enantiomerically pure bicyclic proline derivative and an enantiomerically pure β-hydroxy-α-amino acid.

Key words

azomethine ylide - β-hydroxy-α-amino acid - proline - intramolecular - cycloaddition

7

X-ray Crystal Data: 6 C17H21NO2, M = 271.35, orthorhombic, space group P212121, Z = 4, a = 6.715 (10), b = 13.502 (8), c = 16.73 (2), V = 1517 Å3, d = 1.188 Mg/m3, 1545 independent reflections were collected with MoKα radiation on the MAR research Image Plate system. Data analysis was carried out with the XDS program [8] the structure was solved by direct methods using Shelx86 [9] and refined on F2 using Shelx [10] to R1 0.0686, wR2 0.1937. 8a C23H22N2O4, M = 390.43, orthorhombic, space group P212121-, Z = 4, a = 9.510 (12), b = 9.934 (14), c = 21.23 (2), V = 2006 Å3, d = 1.293 Mg/m3, 3554 independent reflections were collected. The structure was solved by direct methods and refined on F2 to R1 0.0834, wR2 0.2490. 9c C28H24N2O4, M = 452.49, monoclinic, space group P21-, Z = 2, a = 10.857 (12), b = 8.120 (10), c = 28.75 (3), β = 96.895 (i1)°, V = 2516 Å3, d = 1.194 Mg/m3, 4541 independent reflections were collected. The structure was solved by direct methods and refined on F2 to R1 0.1749, wR2 0.4199. 10c C24H25NO6, M = 423.45.31, orthorhombic, space group P212121, Z = 4, a = 11.389 (15), b = 13.320 (14), c = 15.080 (17), V = 2272 Å3, d = 1.238 Mg/m3, 2480 independent reflections were collected. The structure was solved by direct methods and refined on F2 to R1 0.0488, wR2 0.1277. 11c C24H25NO6, M = 423.45.31, orthorhombic, space group P212121, Z = 4, a = 6.212 (10), b = 16.72 (2), c = 20.33 (3), V = 2111 Å3, d = 1.332 Mg/m3, 6680 independent reflections were collected. The structure was solved by direct methods and refined on F2 to R1 0.1078, wR2 0.2857. 15 C25H22N2O5, M = 430.45, orthorhombic, space group P212121, Z = 4, a = 7.481 (10), b = 13.464 (17), c = 21.72 (3), V = 2188 Å3, d = 1.307 Mg/m3, 6487 independent reflections were collected. The structure was solved by direct methods and refined on F2 to R1 0.0996, wR2 0.2057. Atomic co-ordinates, bond lengths and angles and thermal parameters have been deposited with the Cambridge Crystallographic Service.