Synthesis of a 5-oxo-2-Tetrahydrofuranyl Derivative of an Evans Auxiliary via a Novel Reaction Induced by Nucleophiles

Abstract

A 5-oxo-2-tetrahydrofuranyl derivative of an Evans auxiliary could be obtained through a previously unknown ‘rearrangement’ of the oxazolidinone moiety in an α-benzoxy-γ-aldehyde acyl oxazolidinone in 60-97% yields on treatment with a range of ­nucleophiles.

chiral auxiliaries - rearrangements - lactones - ring closure - tandem reactions

References

1 Fuber M. Herbert JM. Taylor RJK. J. Chem. Soc., Perkin Trans. 1  1989,  683 

2

Data for 5a: A white solid, mp 107-109 °C; [α]_D ¹⁵ -190.0 (c 1.0, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 7.50-7.20 (m, 10 H, aromat), 5.34 (dd, J = 9.0, 3.3 Hz, 1 H, H-2), 5.03 (t, J = 8.9 Hz, 1 H, H-7), 4.94 (d, J = 11.2 Hz, 1 H, H-8), 4.65 (d, J = 11.4 Hz, 1 H, H-8), 4.64-4.58 (m, 2 H, H-4 and H-6), 4.13 (t, J = 9.1 Hz, 1 H, H-6), 3.08 (ddd, J = 3.2, 8.6, 14.1 Hz, 1 H, H-3), 2.38 (ddd, J = 6.5, 8.9, 14.7 Hz, 1 H, H-3). ¹³C NMR (75 MHz, CDCl₃): δ = 173.96 (C-1), 156.41 (C-5), 136.86 (q, aromat), 135.83 (q, aromat), 129.70, (aromat, CH), 129.57 (2 C, aromat), 128.42 (2 C, aromat), 128.08 (2 C, aromat), 128.01(aromat), 127.30 (2 C, aromat), 81.95 (C-2), 72.59 (C-4), 72.52 (C-8), 70.08 (C-6), 60.69 (C-7), 32.47 (C-3). FT-IR (film of highly conc. solution in CH₂Cl₂): 1764 cm^-1. MS (EI): m/z (%) = 218(77) [M⁺ - BnOCHCH], 190(32), 164(33), 146(41), 130(27), 104(46), 91(100).

3

The crystallographic data (CCDC 207744) can be obtained free of charge via from the Cambridge Crystallographic Data Centre, 12 Union Road, Cambridge CB2 1EZ, UK; e-mail: [e-mail].

4

Data for 5b(oil): [α]_D ¹⁵ -113.8 (c 0.6, CHCl₃). ¹H NMR (300 MHz, CDCl₃): δ = 7.50-7.20 (m, 10 H), 5.04 (dd, J = 9.1, 5.2 Hz, 1 H), 4.82 (d, J = 11.7 Hz, 1 H), 4.69 (t, J = 9.0 Hz, 1 H), 4.59 (d, J = 11.8 Hz, 1 H), 4.21-4.10 (m, 2 H), 2.24 (ddd, J = 5.5, 7.8, 19.1 Hz, 1 H), 1.81 (dt, J = 13.4, 10.0 Hz, 1 H). ¹³C NMR (75 MHz, CDCl₃): δ = 172.66, 157.93, 139.27, 136.35, 129.60, 129.22, 128.49, 128.22, 128.13, 126.14, 81.36, 73.08, 72.51, 71.06, 55.40, 32.99. FT-IR(film): 1767 cm^-1. MS (EI): m/z (%) = 218(48) [M⁺ - BnOCHCH], 190 (21), 164 (30), 146 (29), 130 (27), 104 (49), 91 (100).

See for example:

5a Evans DA. Science  1988,  240:  420 

5b Compendium of Chiral Auxiliary Applications   Vol. 1-3:  Roos G. Academic Press; San Diego: 2002. and many references cited therein

6 Wissing E. Kleijn H. Boersma J. van Koten G. Recl. Trav. Chim. Pays-Bas  1993,  112:  618 ; and references therein.

7

It is interesting to note that treatment of 6 in anhydrous THF at -78 ºC with 4 did not give any 5 at all but a complicated product mixture.