5493
6. All reactions were performed in ¯ame-dried ¯asks in a dry argon atmosphere and using well-dried solvents and
reagents, all vessels used being protected from daylight with a foil of aluminium during any operation. Protocol
for the nitrosylation of 2a: To a stirred solution of 2a (19 g; 738 mmol) in CH2Cl2 (100 ml) were added
successively, by means of a syringe: (i) pyridine (8.5 ml; 105 mmol); (ii) i-amyl nitrite (14 ml; 105 mmol); (iii)
TMSCl (26.7 ml; 210 mmol). The resulting clear solution was stirred for 24 h at rt (should a TLC indicate the
presence of residual 2a, slight excess (0.2 equiv.) of each reagent will be added in the same order, the stirring being
pursued until complete disappearance of the starting material). The reaction mixture was then poured into 10%
aqueous NaHCO3 (200 ml). After 30 min stirring, the aqueous layer was extracted with CH2Cl2 (2Â50 ml). The
pooled organic extracts were then washed successively with 1 N HCl (2Â150 ml), brine (2Â50 ml), 10% NaHCO3
(50 ml), then brine (20 ml), and dried (MgSO4). Rotoevaporation (without heating) of the solvents left a pale-
yellow powder (21 g) which was recrystallised in CH2Cl2/Et2O to give 2a (19.2 g; 67 mmol; 90.8%) as a bright-
yellow powder; mp 88±89ꢀC (lit.2 mp 87±89ꢀC); H NMR: 1.33 (t, J=7.12 Hz, 3H), 2.4 (s, 3H), 4.42 (q, J=7.12
1
Hz, 2H), 5.06 (s, 2H), 7.31 (m, 2H), 7.63 (m, 2H); 13C NMR: 14.1, 21.8, 58.5, 65.4, 128.5, 130.6, 135.4, 145.9,
152.4. The 3±1 conversions were performed according to Ref. 2 except that the ¯ask containing the basic alumina
(Merck; 3 g/mmol) was ®rst heated in an oven at 300ꢀC for 12 h, then immediately transferred in a desiccator
where it was allowed to cool to rt in vacuo. It was then connected to an argon line, and cooled (ice/methanol)
before the ether was added. After 12 h stirring at rt, on a 7.2 g scale (25 mmol), the diazosulfone 1a was obtained
as bright-yellow needles (3.3 g; 67.2%) after recrystallisation from a 2:1 ether:hexane mixture.
1
7. Selected data: 2b: H NMR: 1.04 (t, J=6.8 Hz, 3H), 1.56 (d, J=6.7 Hz, 3H), 2.39 (s, 3H), 3.86 (q, J=6.8 Hz),
4.85±5.1 (m, 1H), 5.57 (d, J=10.3 Hz, 1H (NH)), 7.29 (m, 2H), 7.75 (m, 2H); 13C NMR: 13.2, 14.5, 21.7, 61.6,
67.4, 129.5, 129.8, 133.4, 145.2, 154.8; 3b: 1H NMR: 1.45 (t, J=7.15 Hz, 3H), 1.67 (d, J=7.2 Hz, 3H), 2.43 (s, 3H),
4.53 (qd, J=7.15, 1.6 Hz, 2H), 5.75±5.9 (m, 1H), 7.34 (m, 2H), 7.68 (m, 2H); 13C NMR: 13.3, 14.5, 21.8, 61.7, 67.4,
1
129.4, 129.8, 133.3, 145.3, 154.9; 1b: 13C NMR: 8.95, 21.7, 59.3, 126.7, 130.1, 139.3, 144.4. H and 13C NMR at
200 and 50 MHz, respectively, in CDCl3.
8. Crystal data for 1a: C8H8N2O2S, M.W.=196.23, colourless, orthorhombic, a=7.791(3), b=20.389(6), c=5.653(2)
A, Z=4, dcalc=1.45 g cm^3, ꢀ=2.906 mm^1, space group P212121. Data were collected on a crystal of dimensions
0.35Â0.35Â0.12 mm3 using a Philips PW1100/16 automatic diractometer and graphite monochromated CuKꢁ
radiation (l=1.5418 A) at ^100ꢀC. 672 re¯ections measured (3ꢀ<2ꢂ<54ꢀ) with 603 having I>3 ꢃ(I). Empirical
absorption corrections, transmission factors between 0.28 and 1. The structure was determined using direct
methods. Hydrogen atoms were introduced in structure factor calculations as ®xed contributors with d(X-
H)=0.95 A and B(H)=1.3*Beqv(X) A2. Re®nements against l Fl using the OpenMoleN package on a DEC
Alpha workstation and anisotropic temperature factors for all non-hydrogen atoms. The absolute structure was
determined re®ning Flack's x parameter. Final results: R(F)=0.052, Rw(F)=0.068, GOF=1.657.
9. (a) Regitz, M.; Waas, G. Diazo Compounds. Properties and Synthesis; Academic Press: London, 1986; (b) To be
compared with the 1.66 A value obtained for the corresponding C±S bond in anionised benzyl phenylsulfone
(Reetz, M. T.; Hutte, S.; Goddard, R. Eur. J. Org. Chem. 1999, 2475±2478 and references cited therein); (c)
Cerioni, G.; Culeddu, N.; Saba, A. Magn. Reson. Chem. 1993, 31, 829±831; (d) Engberts, J. B. F. N.; Zwanenburg,
B. Tetrahedron 1968, 24, 1737±1754.