Preparation of chiral α-diazophosphonic acid derivatives

Article abstract of DOI:10.1016/S0957-4166(01)00287-7

The chiral α-diazophosphonic acid derivatives 3, 6 and 8 were prepared from (-)-ephedrine and (S,S)-N,N′-dimethyl-1,2-diaminocyclohexane; preliminary experiments suggest that the chiral auxiliary exerts little influence in the dirhodium(II) acetate cataly

Full text of DOI:10.1016/S0957-4166(01)00287-7

TETRAHEDRON:
ASYMMETRY
Pergamon
Tetrahedron: Asymmetry 12 (2001) 1657–1661
Preparation of chiral a-diazophosphonic acid derivatives
Christopher J. Moody,a,* C. Neil Morfitta and Alexandra M. Z. Slawinb
aSchool of Chemistry, University of Exeter, Stocker Road, Exeter EX4 4QD, UK
bSchool of Chemistry, University of St. Andrews, Fife, Scotland KY16 9ST, UK
Received 8 June 2001; accepted 21 June 2001
Abstract—The chiral a-diazophosphonic acid derivatives 3, 6 and 8 were prepared from (−)-ephedrine and (S,S)-N,N%-dimethyl-
1,2-diaminocyclohexane; preliminary experiments suggest that the chiral auxiliary exerts little influence in the dirhodium(II)
acetate catalysed OꢀH and NꢀH insertion reactions. © 2001 Elsevier Science Ltd. All rights reserved.
1. Introduction
zophospholidine and trans-1,2-bis(N-methylamino)-
cyclohexane-derived benzodiazaphosphole frameworks;
both of these systems have been shown to be effective
chiral auxiliaries in phosphorus chemistry.12–14 Thus,
benzylphosphonic acid diethyl ester was converted into
the phosphonic acid dichloride, reaction of which with
(−)-ephedrine gave the desired 2-benzyl-1,3,2-oxaza-
phospholidine as described in the literature (Scheme
1).13 The two diastereomers (epimeric at phosphorus)
were readily separated to give the (2R)-isomer 1 and
the (2S)-isomer 2.
Despite their ready availability,1 a-diazophosphonates
and related derivatives have found rather limited use in
organic synthesis, their major role being the use of
dimethyl (or diethyl) diazomethylphosphonate in the
preparation of alkynes.2,3 Although the rhodium carbe-
nes formed in the dirhodium(II) acetate catalysed
decomposition of diazophosphonates undergo typical
reactions such as intramolecular cyclopropanation,4
intramolecular CꢀH insertion,5 and OꢀH and NꢀH
insertion reactions,6–8 such reactions are much less used
than the corresponding reactions of their diazocarbonyl
counterparts.9 In an attempt to extend the utility of
a-diazophosphonic acid derivatives in synthesis, we
have prepared the first examples of chiral a-diazophos-
phonyl compounds, and briefly investigated the
diastereoselectivity in their XꢀH (X=O, N) insertion
reactions, having previously studied the corresponding
reactions of chiral a-diazoesters.10,11
Initial attempts to prepare the corresponding diazo
compounds centred on direct diazo-transfer.1 However,
the use of 4-toluenesulfonyl azide as diazo-transfer
reagent proved unsatisfactory, and it was only when 1
was treated with LDA followed by 4-nitrobenzenesul-
fonyl azide15 that the diazo compound 3 was formed,
along with the corresponding azide 4 (Scheme 2). The
competition being azido- and diazo-transfer has been
noted previously, for example, by Evans et al.16 Unfor-
tunately, the diazo compound 3 and azide 4 proved
extremely difficult to separate, and eventually the diazo
compound was only obtained in low yield, still contam-
inated with traces of the azide.
2. Results and discussion
The a-diazophosphonic acid derivatives chosen for
study were based on the (−)-ephedrine-derived oxa-
Scheme 1.
* Corresponding author.
0957-4166/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved.
PII: S0957-4166(01)00287-7

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C. J. Moody et al. / Tetrahedron: Asymmetry 12 (2001) 1657–1661
Scheme 2.
An alternative route was therefore developed in which
the diazo group was already present in the precursor.
Diethyl a-diazobenzyl phosphonate 517 was converted
into the corresponding phosphonic acid by treatment
with trimethylsilyl bromide; reaction with oxalyl chlo-
ride followed by (−)-ephedrine gave a mixture of the
diastereomeric diazo compounds (Scheme 3). The
diastereomers were readily separated and gave the pure
diazophosphonyl derivatives 3 and 6 albeit in extremely
poor yield.
With three homochiral a-diazophosphonic acid deriva-
tives available, a brief investigation of their reactivity
was carried out to ascertain if the derived rhodium
carbenes exhibited any diastereoselectivity in their sub-
sequent insertion reactions. Therefore the diazophos-
phonyl derivative 8 was treated with a catalytic amount
of dirhodium(II) acetate in the presence of 2-propanol
or benzyl carbamate. Unfortunately no products result-
ing from carbene insertion into the respective OꢀH or
NꢀH bonds could be isolated. The corresponding reac-
tions of the P-stereogenic diazo compounds 3 and 6 did
however lead to the formation of insertion products in
good yield (Scheme 5), although the diastereoselectivity
of the reactions (as determined by 31P NMR analysis of
the initial product mixture) was poor (15–32%).
The synthesis of the diazo compound 8 proved simpler;
the known diazophosphole-2-oxide 714 was subjected to
the above diazo-transfer conditions, and although the
azide 9 was also formed, the desired diazo compound 8
could be readily obtained pure by recrystallisation
(Scheme 4). The crystals of 8 proved suitable for analy-
sis by X-ray crystallography, which confirmed the
structure (Fig. 1).
3. Conclusion
We have prepared the first examples of chiral a-dia-
zophosphonic acid derivatives. Initial experiments (and
the X-ray structure of compound 8) suggest that the
two chiral auxiliaries investigated exert little influence
over the subsequent reactions of the derived rhodium
carbenes, in direct contrast to similar reactions of dia-
zoesters, R*O2CC(ꢁN2)Ph, where the chiral group can
impart significant asymmetric induction (up to ꢀ75%
d.e.) in OꢀH insertion reactions.
4. Experimental
4.1. General experimental
Figure 1. X-Ray crystal structure of (3aS,7aS)-2-diazobenzyl-
1,3,3a,4,5,6,7,7a-octahydro-1,3-dimethyl-1H-1,3,2l5-benzodi-
azaphosphole-2-oxide 8.
Commercially available reagents were used throughout
without further purification; solvents were dried by
standard procedures. Light petroleum refers to the
Scheme 3.
Scheme 4.

C. J. Moody et al. / Tetrahedron: Asymmetry 12 (2001) 1657–1661
1659
Scheme 5.
fraction with bp 40–60°C. Analytical TLC was carried
out using aluminium-backed plates coated with Merck
Kieselgel 60 GF254. Plates were visualised under UV
light at 254 nm. Flash chromatography was carried out
using Merck Kieselgel 60 H or Matrex silica 60. NMR
spectra were recorded on a Bruker AM300 or a Bruker
Avance DRX 400 spectrometer at the frequencies
stated. Mass spectra were obtained using a Kratos
Profile HV3 spectrometer or at the EPSRC Mass Spec-
trometry Service (Swansea).
and the azido phosphonate 4. After two further chro-
matographic purifications, the title compound was
obtained as an oil (81 mg, 19%), which still contained
trace amounts of the azide 4; data for the diazophos-
phonate is given below.
4.4. (2R,4S,5R)-2-(a-Diazobenzyl)-3,4-dimethyl-2-oxo-
5-phenyl-1,3,2l5-oxazaphospholidine 3 and (2S,4S,5R)-
2-(a-diazobenzyl)-3,4-dimethyl-2-oxo-5-phenyl-1,3,2l5-
oxazaphospholidine 6
4.2. (2R,4S,5R)-2-Benzyl-3,4-dimethyl-2-oxo-5-phenyl-
1,3,2l5-oxazaphospholidine 1 and (2S,4S,5R)-2-benzyl-
3,4-dimethyl-2-oxo-5-phenyl-1,3,2l5-oxazaphospholidine
2
Diethyl (a-diazo)benzyl phosphonate 517 (5.00 g, 22
mmol)
was
dissolved
in
freshly
distilled
dichloromethane (10 mL) under argon and trimethyl-
silyl bromide (5.8 mL, 43.9 mmol) was added. The
mixture was stirred overnight, concentrated, and the
resulting oil was taken up again in dichloromethane (10
mL) under argon. Oxalyl chloride (4.2 mL, 48.4 mmol)
and one drop of dry dimethylformamide were added
and the mixture stirred for 0.5 h and concentrated. The
resulting oil was taken up in anhydrous toluene (10
mL) under argon while in a separate flask (−)-ephedrine
(3.6 g, 21.8 mmol) was dissolved in toluene (10 mL)
with molecular sieves and triethylamine (6 mL). This
was then added dropwise to the phosphonate solution
over a 0.5 h period before leaving to stir overnight.
Water (20 mL) was added and the solution extracted
with dichloromethane (3×50 mL); the combined organic
extracts were dried (sodium sulfate), filtered and con-
centrated to an oil. This oil was chromatographed (2:3
ethyl acetate:light petroleum) to separate the
diastereomers and give the (2R,4S,5R)-diastereomer 3
as a yellow oil (126 mg, 1.7%), [h]2D1=−43.2 (c 1,
CHCl3); (Found: M+, 327.1133. C17H18N3O2P requires:
327.1137); wmax (film)/cm−1 2976, 2075, 1660, 1598,
1450, 1290, 1255, 1173, 1052, 980, 888, 853, 751, 726,
700; lH (400 MHz; CDCl3) 0.89 (3H, d, J=6.6,
MeCH), 2.75 (3H, d, J=10.5, NMe), 3.70 (1H, m,
Prepared from dichlorobenzyl phosphonate and (−)-
ephedrine according to the literature procedure.13 The
diastereomers were separated using chromatography
(1:19; propan-2-ol:ethyl acetate) to give the (2R,4S,5R)-
diastereomer 1 as a solid (31%), mp 134–136°C (lit.,13
mp 133–134°C) and the (2S,4S,5R)-diastereomer 2 as a
solid (40%), mp 171–173°C (lit.,13 mp 169–171°C).
4.3. (2R,4S,5R)-2-(a-Diazobenzyl)-3,4-dimethyl-2-oxo-
5-phenyl-1,3,2l5-oxazaphospholidine 3
A solution of (2R,4S,5R)-oxazaphospholidine 1 (389
mg, 1.3 mmol) in THF (10 mL) was cooled to −78°C
and treated with a solution of LDA (2 M; 1.4 mL, 2.8
mmol). After 30 min, a solution of 4-nitrobenzenesul-
fonyl azide15 (555 mg, 2.4 mmol) in THF (10 mL) was
added and the mixture allowed to warm up to room
temperature overnight. Phosphate buffer (pH 7; 10 mL)
was added, and the mixture extracted with
dichloromethane; the organic extracts were dried
(sodium sulfate), filtered and concentrated to an oil.
This was then chromatographed (40% EtOAc–light
petroleum) to give a mixture of the diazophosphonate 3

1660
C. J. Moody et al. / Tetrahedron: Asymmetry 12 (2001) 1657–1661
CHN), 5.54 (1H, dd, J=6.4, 4.4, CHO), 7.18–7.40
(10H, m, ArH); lC (100 MHz; CDCl3) 14.8 (Me, d,
J=1.2), 28.4 (CH, d, J=6.1), 50.5 (CN2, d, J=209.7),
59.2 (Me, d, J=11.6), 82.5 (CH), 124.6 (CH, d, J=3.8),
125.9 (CH), 126.1 (CH), 127.5 (C, d, J=9.5), 128.3
(CH), 128.5 (CH), 129.3 (CH), 135.9 (C, d, J=6.0); lP
(123 MHz; CDCl3) 31.9; m/z (EI) 327 (M+, 4%), 210
(2), 194 (27), 77 (46); and the (2S,4S,5R)-diastereomer
6 (99 mg, 1.4%) as a yellow oil, [h]2D1=−15.6 (c 1,
CHCl3); (Found: M+, 327.1133); wmax (film)/cm−1 3062,
2976, 2931, 2063, 1653, 1598, 1497, 1453, 1331, 1254,
1216, 1185, 1063, 975, 884, 857, 813, 753, 701; lH (400
MHz; CDCl3) 0.60 (3H, d, J=6.6, MeCH), 2.83 (3H, d,
J=9.9, NMe), 3.77 (1H, m, CHN), 5.87 (1H, d, J=6.4,
CHO), 7.17–7.47 (10H, m, ArH); lC (100 MHz; CDCl3)
14.2 (Me, d, J=1.1), 29.2 (CH, d, J=6.7), 49.9 (CN2,
d, J=212.7), 60.1 (Me, d, J=10.6), 80.2 (CH, d, J=
1.2), 125.5 (CH), 125.6 (C, d, J=10.0), 125.7 (CH, d,
J=4.5), 126.2 (CH), 127.2 (C, d, J=10.5), 128.2 (CH),
128.5 (CH), 129.1 (CH); lP (123 MHz; CDCl3) 31.1;
m/z (EI) 327 (M+, 11%), 299 (23), 194 (66), 210 (20), 77
(88).
4.6. (2R,4S,5R)-2-(a-Isopropoxybenzyl)-3,4-dimethyl-2-
oxo-5-phenyl-1,3,2l5-oxazaphospholidine 10
The diazophosphonate 3 (44.5 mg, 0.12 mmol) was
dissolved in toluene (2 mL), and isopropyl alcohol (110
ml, 1.4 mmol) and rhodium acetate (catalytic) were
added before heating to 110°C for 1 h. The mixture was
concentrated and the resulting oil analysed by 31P
NMR; a de of 32% was determined. The oil was
chromatographed (3:2; ethyl acetate:light petroleum) to
obtain one diastereomer of the title compound (14 mg,
29%) as an oily solid, [h]2D2=+3 (c 1, CHCl3); (Found:
M+, 359.1651. C20H26NO3P requires: 359.1650); wmax
(film)/cm−1 2970, 2929, 2877, 1452, 1327, 1375, 1255,
1219, 1061, 982, 899, 854, 702; lH (400 MHz; CDCl3)
0.75 (3H, d, J=6.6, MeCH), 1.19 (3H, d, J=6.1,
CHMe2), 1.21 (3H, d, J=6.1, CHMe2), 2.26 (3H, d,
J=9.1, NMe), 3.66 (1H, m, CHN), 3.77 (1H, heptet,
J=6.1, CH6 Me2), 5.04 (1H, d, J=18.3, PCH), 5.62 (1H,
dd, J=3.6, 6.4, CHO), 7.26–7.60 (10H, m, ArH); lC
(100 MHz; CDCl3) 14.2 (Me), 21.6 (Me), 22.9 (Me),
29.5 (Me, d, J=4.5), 58.7 (CH, d, J=9.0), 72.5 (CH, d,
J=10.5), 76.9 (CH, d, J=148.3), 82.7 (CH, d, J=3.0),
126.1 (CH), 127.1 (CH), 127.4 (CH, d, J=65.2), 128.0
(CH, d, J=58.4), 128.1 (CH, d, J=21.0), 128.3 (CH),
136.6 (C), 136.8 (C, d, J=5.2); lP (123 MHz; CDCl3)
36.6; m/z (EI) 360 (MH+, 6%), 316 (2), 301 (10), 149
(93), 77 (61); and the other diastereomer (14 mg, 29%)
as an impure oil, (Found: M+, 359.1650); wmax (film)/
cm−1 3062, 3032, 2979, 2931, 1740, 1716, 1645, 1495,
1452, 1373, 1227, 1176, 1059, 995, 748, 690; lH (400
MHz; CDCl3) 0.72 (3H, d, J=6.6, MeCH), 1.21 (3H, d,
J=6.1, CHMe2), 1.25 (3H, d, J=6.1, CHMe2), 2.79
(3H, d, J=9.2, NMe), 3.47–3.56 (1H, m, CHN), 3.77
4.5. (3aS,7aS)-2-Diazobenzyl-1,3,3a,4,5,6,7,7a-octahy-
dro-1,3-dimethyl-1H-1,3,2l5-benzodiazaphosphole-2-
oxide 8
(3aS,7aS)-2-Benzyloctahydro-1,3-dimethyl-1H-1,3,2l5-
benzodiazaphosphole-2-oxide 7 (prepared from (S,S)-
N,N%-dimethyl-1,2-diaminocyclohexane by the literature
method for the (R,R)-isomer14) (1.24 g, 4.0 mmol) was
dissolved in freshly distilled THF (50 mL) under argon.
This solution was cooled to −78°C before the addition
of n-butyllithium (1.6 M; 3.3 mL, 5 mmol) over a 0.5 h
period. The mixture was stirred for a further 0.5 h
before the addition of 4-nitrobenzenesulfonyl azide15
(844 mg, 3.6 mmol) in THF (50 mL). After stirring for
4 h, phosphate buffer (pH 7; 10 mL) was added. The
solution was then extracted with dichloromethane; the
organic extracts were dried (sodium sulfate), filtered
and concentrated. The resulting oil was chro-
matographed column (2:98; methanol:dichloromethane)
to give a mixture of diazophosphonate 8 and azido
phosphonate 9. The mixture was recrystallised twice
from n-pentane to give the title compound (212 mg,
31%) as a orange solid, mp 86–90°C; [h]2D1=+7.3 (c 1,
CHCl3); (Found: C, 59.7; H, 7.2; N, 18.1. C15H21N4OP
requires: C, 59.2; H, 7.0; N, 18.4%); (Found: M+,
304.1455. C15H21N4OP requires: 304.1453); wmax (film)/
cm−1 2938, 2865, 2817, 2071, 2054, 1120, 1289, 1255,
1174, 1026, 1010, 958, 805, 750; lH (400 MHz; CDCl3)
1.15–1.45 (4H, m), 1.84–2.11 (4H, m), 2.52 (3H, d,
J=8.8, NMe), 2.60–2.66 (1H, m, NCH), 2.66 (3H, d,
J=9.0, NMe), 2.90–2.93 (1H, m, NCH), 7.11–7.36 (5H,
m, ArH); lC (100 MHz, CDCl3) 24.1 (CH2, d, J=1.5),
24.2 (CH2), 28.1 (Me), 28.3 (CH2, d, J=10.5), 28.4
(CH2, d, J=8.24), 28.4 (Me, d, J=2.2), 49.7 (CN2, d,
J=180.5), 63.6 (CH, d, J=7.5), 65.4 (CH, d, J=8.2),
124.2 (CH, d, J=3.0), 125.1 (CH), 128.7 (C, d, J=9.0),
128.9 (CH); lP (162 MHz; CDCl3) 32.5; m/z (EI) 304
(M+, 1%), 277 (30), 276 (M+−N2, 13), 229 (100), 187
(34), 171 (72), 110 (31), 77 (34),
(1H, m, CH6 Me2), 4.95 (1H, dd, J=0, 6.6, CHO), 5.05
(1H, d, J=14.4, PCH), 7.26–7.37 (10H, m, ArH); lC
(100 MHz; CDCl3) 15.0 (Me), 21.3 (Me), 23.1 (Me),
29.0 (Me, d, J=5.5), 58.7 (CH, d, J=9.4), 71.4 (CH, d,
J=12.1), 76.9 (CH, d, J=147.8), 82.4 (CH, d, J=2.7),
126.1–128.3 (6×CH), 136.5 (C), 136.7 (C, d, J=4.5); lP
(123 MHz; CDCl3), 36.5; m/z (EI) 360 (MH+, 7%), 316
(1), 301 (4), 149 (94), 77 (31).
4.7. (2S,4S,5R)-2-(a-Isopropoxybenzyl)-3,4-dimethyl-2-
oxo-5-phenyl-1,3,2l5-oxazaphospholidine 11
A mixture of the diazophosphonate 6 (42.0 mg, 0.12
mmol), toluene (2 mL), isopropyl alcohol (20 ml, 1.5
mmol) and rhodium acetate (catalytic) was heated at
80°C for 1 h. The mixture was concentrated and the
resulting oil analysed by 31P NMR; a d.e. of 16% was
determined. The oil was chromatographed (3:2; ethyl
acetate:light petroleum) to obtain one diastereomer of
the title compound (14 mg, 30%) as an oil, (Found: M+,
359.1660. C20H26NO3P requires: 359.1650); wmax (film)/
cm−1 3415, 3062, 3032, 2972, 2929, 1768, 1691, 1647,
1495, 1452, 1381, 1331, 1248, 1215, 1184, 1117, 1090,
1065, 978, 889, 742, 702; lH (300 MHz; CDCl3) 0.89
(3H, d, J=6.6, MeCH), 1.19 (3H, d, J=6.1, CHMe2),
1.26 (3H, d, J=6.1, CHMe2), 2.45 (3H, d, J=8.0,
NMe), 3.64 (1H, heptet, J=6.1, CH6 Me2), 3.72–3.80
(1H, m, CHN), 5.07 (1H, d, J=17.6, PCH), 5.78 (1H,
d, J=6.3, CHO), 7.28–7.57 (10H, m, ArH); lC (100

C. J. Moody et al. / Tetrahedron: Asymmetry 12 (2001) 1657–1661
1661
,
MHz; CDCl3) 14.6 (Me), 20.9 (Me), 23.2 (Me), 31.2 (Me,
d, J=4.5), 61.3 (CH, d, J=9.0), 70.7 (CH, d, J=10.5),
75.1 (CH, d, J=148.3), 80.1 (CH, d, J=3.0), 126.0 (CH),
127.7 (CH, J=5.2)), 128.0 (CH), 128.1 (CH), 128.3 (CH),
128.4 (CH), 136.2 (C), 136.5 (C, d, J=5.2); lP (123 MHz;
CDCl3) 35.1; m/z (EI) 359 (M+, 0.3%), 118 (17). 91 (13),
77 (14), 58 (15); a mixture of diastereomers (6 mg, 12%),
and the other diastereomer (8 mg, 17%) as an oil; (Found:
M+, 359.1650); wmax (film)/cm−1 3406, 3062, 2970, 2926,
1734, 1647, 1454, 1373, 1236, 1066, 1028, 976, 744, 702;
lH (300 MHz; CDCl3) 0.87 (3H, d, J=6.6, MeCH), 1.20
(3H, d, J=6.4, CHMe2), 1.28 (3H, d, J=6.4, CHMe2),
8.8367 (3), b=9.9769 (3), c=18.3490 (5) A, V=1617.70
3
(9) A , zcalcd 1.250 g/cm3, Z=4, v(Cu Ka)=0.175 mm−1;
,
7160 reflections measured, 2436 independent, observed
with I>2|(I) 2296 to yield R=0.0597.
Acknowledgements
We thank the EPSRC for a studentship to (C.N.M.) and
the EPSRC Mass Spectrometry Service at Swansea for
mass spectra.
2.43 (3H, d, J=8.1, NMe), 3.60–3.74 (2H, m, CH6 Me2
and CHN), 5.05 (1H, d, J=17.6, PCH), 5.78 (1H, d,
J=6.4, CHO), 7.28–7.40 (10H, m, ArH); lC (100 MHz;
CDCl3) 14.2 (Me), 20.9 (Me), 23.1 (Me), 29.5 (Me, d,
J=4.5), 61.0 (CH, d, J=9.0), 70.8 (CH, d, J=10.5), 74.5
(CH, d, J=148.3), 79.7 (CH, d, J=3.0), 126.1 (CH),
127.1 (CH), 127.4 (CH, d, J=65.2), 128.0 (CH, d,
J=58.4), 128.1 (CH, d, J=21.0), 128.3 (CH), 136.6 (C),
136.8 (C, d, J=5.2); lP (123 MHz; CDCl3) 35.6; m/z (EI)
359 (M+, 0.2%), 122 (66). 91 (49).
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4096–4105.
16. Evans, D. A.; Britton, T. C.; Ellman, J. A.; Dorow, R. L.
J. Am. Chem. Soc 1990, 112, 4011–4030.
A mixture of the diazophosphonate 3 (46.1 mg, 0.14
mmol), toluene (2 mL), benzyl carbamate (45.7 mg, 0.3
mmol) and rhodium acetate (catalytic) was heated under
nitrogen to 80°C for 5 h. The mixture was concentrated
and the resulting oil analysed by 31P NMR; a de of 15%
was determined. The oil was chromatographed (2:3; ethyl
acetate:light petroleum) to give the title compound as an
inseparable mixture of diastereoisomers (36 mg, 56%) as
an oil, (Found: MH+, 451.1784. C25H27N2O4P+H
requires: 451.1787); wmax (film)/cm−1 3216, 3063, 3027,
2914, 1721, 1532, 1448, 1245, 1063, 1023, 979; lH (400
MHz; CDCl3) 0.74 (3H, 2×d, J=6.6, CHMe), 2.17 (3H,
d, J=9.3, NMe), 2.65 (2H, m, 2×CH), 3.38–3.57 (1H, m,
PCH), 5.02–5.30 (2H, m, CH6 2Ph), 5.97 (1H, d, J=5.3,
NH), 7.22–7.52 (15H, m, ArH); lC (100 MHz; CDCl3)
(major and minor) 14.2 and 14.3 (Me), 28.6 and 29.1
(Me), 54.8 and 53.6 (CH), 59.1 and 58.4 (CH), 67.3 and
67.2 (CH2), 82.0 and 82.7 (CH), 126.2–128.8 (9×CH, for
both diastereomers), 135.71 and 135.68 (C), 135.76 and
135.9 (C), 136.15 and 136.11 (C), lP (123 MHz; CDCl3)
35.8 and 36.5; m/z (CI) 451 (MH+, 20%0, 150 (65), 72
(100).
4.9. Crystal data
Rigaku AFC7S diffractometer with Cu radiation. T=
293 K, all non-H atoms refined anisotropically.18
17. Regitz, M.; Anschu¨tz, W.; Liedhegener, A. Chem. Ber.
1968, 101, 3734–3743.
18. The authors have deposited atomic coordinates with the
Cambridge Crystallographic Data Centre. The coordi-
nates can be obtained on request from The Director,
Cambridge Crystallographic Data Centre, 12 Union
Road, Cambridge CB2 1EZ, UK.
4.10. (3aS,7aS)-2-Diazobenzyl-1,3,3a,4,5,6,7,7a-octahy-
dro-1,3-dimethyl-1H-1,3,2l5-benzodiazaphosphole-2-
oxide 8
C15H21N4OP, M=304.33, orthorhombic, P212121, a=
.