P(n-Bu)3 catalyzed reactions of salicyl n-thiophosphinyl imines with allenylphosphonates: Synthesis of phosphono-chromans

Article abstract of DOI:10.1002/jhet.2071

A phosphine [P(n-Bu)₃]-catalyzed reaction for the synthesis of phosphono-chromans from allenylphosphonates and salicyl N-thiophosphinyl imines has been described and compared with reactions for phosphorus-free allenes. The products are (β,γ)-cyclized and are obtained in good yields (57-83%). A key product is characterized by X-ray crystallography.

Full text of DOI:10.1002/jhet.2071

760
P(n-Bu)3 Catalyzed Reactions of Salicyl N-Thiophosphinyl Imines with
Vol 51
Allenylphosphonates: Synthesis of Phosphono-Chromans
*
R. Rama Suresh, R. N. Prasad Tulichala, Ramesh Kotikalapudi, and K. C. Kumara Swamy
School of Chemistry, University of Hyderabad, Hyderabad 500 046, Andhra Pradesh, India
*
E-mail: kckssc@uohyd.ernet.in
Received March 14, 2013
DOI 10.1002/jhet.2071
Published online 3 December 2013 in Wiley Online Library (wileyonlinelibrary.com).
A
phosphine [P(n-Bu)3]-catalyzed reaction for the synthesis of phosphono-chromans from
allenylphosphonates and salicyl N-thiophosphinyl imines has been described and compared with reactions
for phosphorus-free allenes. The products are (β,γ)-cyclized and are obtained in good yields (57–83%). A
key product is characterized by X-ray crystallography.
J. Heterocyclic Chem., 51, 760 (2014).
INTRODUCTION
had found that the allenylphosphonates differ in terms of
reactivity compared with phosphorus-free allenes. Whether
this is so in phosphine catalyzed reactions also or not was
one of the things that we were interested in. Herein, we report
phosphine catalyzed reaction of allenylphosphonates with
salicyl-N-thiophosphinyl imines in the presence of phos-
phine also gives chromans.
Lewis base catalysis exploiting phosphines and amines
has emerged as a prominent area in organic synthesis [1].
In particular, phosphine catalysis in the reactions using
allenes has been demonstrated for the development of
new annulation providing various carbo- and hetero-cycles
[1,2]. Addition of a Lewis base to allenoates results in the
generation of a zwitterionic species (1,3-dipole), which
can react with aldehydes, α,β-unsaturated ketones, imines,
activated alkenes, salicylaldehydes, and so on to give di-
verse products depending on the nature of nucleophile
and the substituent on the allenoate [2]. Chromenes and
chromans are widespread in natural products and have
attracted much attention in diverse areas including physical
chemistry (photochromism) and medicinal chemistry (anti
HIV, anticancer, antimicrobial, inhibitory effect on hista-
mine release, antihypertensive, and antiviral activity [3]).
Thus, a number of research groups have developed differ-
ent methodologies to synthesize these compounds [4].
Recently, Huang reported the phosphine catalyzed domino
reactions of salicyl-N-thiophosphinyl imines with allenoate
to afford cis-2,3-dihydrobenzofurans or functionalized
chroman derivatives in good yields under mild conditions
[5]. Our research group has recently reported that
allenylphosphonates react with substituted salicylaldehydes
in the presence of DBU to afford phosphono-chromenes in
good yields [6]. We envisioned that allenylphosphonates
on reaction with salicyl-N-thiophosphinyl imines could lead
to functionalized phosphono-chromans [7]. In our earlier
papers on allene chemistry [8], on several occasions, we
RESULTS AND DISCUSSION
We first treated the allenylphosphonate 2a with
N-thiophosphinyl imine 1a (cf. Scheme 1) in the presence
of various bases and in different solvents to optimize the
reaction conditions. The results are summarized in Table 1.
It was found that the reaction of allenylphosphonate 2a
with N-thiophosphinyl imine 1a led to the expected prod-
uct 3a in poor yield by using PPh3 (20 mol %) as the base
and DMSO as the solvent (Table 1 entry 1). The reaction
was not complete, and the 31P NMR of the reaction
mixture showed approximately 50% of the allene 1a
remaining. When the reaction was performed under the
conditions previously reported from our laboratory [6],
instead of the expected product 3a, phosphono-chromenes
4 (E and Z) were obtained (entry 2). Use of K2CO3 or P
(n-Bu)3 as the base also afforded the chromene 4 [31P
NMR evidence] (Table 1, entries 3 and 4). No desired
product was observed by using the base PPh3, and
dichloromethane or dimethylformamide as the solvent (en-
tries 5 and 6); also the product formation was negligible in
toluene or THF (entries 7 and 8). Interestingly, the reaction
proceeded well in CH3CN to lead to the expected product
© 2013 HeteroCorporation

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Phosphine Catalyzed Synthesis of Phosphono-chromans
761
Scheme 1. Reaction of 1a and 2a to form phosphono-chroman 3a.
all the cases except for 6a and b. The major isomer had the
Z-configuration (vide infra). In the case of 6a–b, the Z-isomer
was isolated in pure state. For the identification of E- and Z-
1
isomers, H and 13C NMR spectra were quite useful. In the
1H NMR, signals for the CH2(CHNP(S)Ph2) protons appear
as a multiplet in the region δ 3.02–3.14 for the E-isomer,
whereas for the Z-isomer, the signals appear up-field
at δ ~2.78–2.88 (cf. Figure 1). In the 13C NMR spectra, the
1J(P–C) value for the E-isomer [~195.6 Hz] was higher than
that for the Z-isomer [~173.4 Hz]. The structure of Z-isomer
of 3a was determined by X-ray crystallography (Figure 2) [9].
The double bond between C6 and C7 was confirmed by the dis-
tance [C(6)–C(7) 1.346(8) Å], whereas the Z-stereochemistry
at this double bond was clearly shown by the attached
substituents. On the basis of these data, we could assign the
31P NMR chemical shifts for all the other compounds. Thus,
the signal for the E-isomer [δ(P) = 14.5] appeared downfield
compared with that for the Z-isomer [δ(P) = 10.4].
In continuation of the previous work, we also treated the
allenylphosphonate 2a with 2-hydroxybenzaldehyde
phenylhydrazone 7 (cf. Scheme 3) in the presence of P
(n-Bu)3 as the base and THF as the solvent. No desired
product was observed in this reaction; instead, we obtained
the phosphono-chromenes 4 (E/Z), which were previously
reported in our laboratory [6].
Table 1
Screening of reaction conditions for the optimization of product 3a.
Temperature
(°C)/time (h)
Entry
Catalyst
Solvent
Yield %a
1
2
3
4
5
6
7
8
PPh3
DBU
K2CO3
P(n-Bu)3
PPh3
PPh3
PPh3
PPh3
PPh3
DMSO
DMSO
DMSO
DMSO
DCM
80/16
80/12
80/8
50
b
b
b
80/10
40/18
80/18
80/18
50/12
80/12
60/12
60/12
n.r.
n.r.
8
DMF
Toluene
THF
CH3CN
THF
6
9
10
11
56
78
36
P(n-Bu)3
P(n-Bu)3
CONCLUSIONS
Toluene
In conclusion, we have demonstrated the synthesis of
various phosphono-chromans catalyzed by P(n-Bu)3 from
the corresponding allenylphosphonates and salicyl-
N-thiophosphinyl imines in moderate to good yields.
aYield of 3a (E + Z) based on 31P NMR spectra of the reaction mixtures.
bIn these cases, chromene 4 (quantitative yield) was obtained.
3a (E + Z) in moderate yields (entry 9). It is noteworthy
that use of P(n-Bu)3 as the base in toluene medium also
led to the product 3a [31P NMR] with lower yield (entry
11); however, there were some side products also. Hence,
we continued with P(n-Bu)3 in THF as the medium. Thus,
these phosphine-catalyzed reactions of allenylphosphonates
follow the same pathway as the phosphorus-free allenes.
The chroman product 3a shows two sets of dominant signals
corresponding to the E and Z isomers, the first one at 58.8/
10.1 (Z-isomer) and the second set at 58.9/ 14.1 (E-isomer).
There are also additional signals at the thiophosphinate region
[δ ~48, 57], but these do not correspond to the products from
the allene; an unassigned minor signal at δ 16.5 is also seen.
By using the previous conditions, we then conducted the
reaction of N-thiophosphinyl imines 1a and 1b with
allenylphosphonates 2a–e and allenylphosphine oxide 5 for
the synthesis of different phosphono-chromans 3a–j and
phosphinoyl-chromans 6a–b, respectively, and also for
checking the scope and limitations of the reaction (Scheme 2
(a and b)). The yields and E/Z ratio of the compounds based
on the 31P NMR spectra of the reaction mixtures were
presented in Table 2. We separated the individual isomers in
EXPERIMENTAL
General. Solvents were dried according to known methods
as appropriate [10]. H, 13C, and 31P NMR spectra (1H-400 or
1
500 MHz, 13C-100 or 125 MHz, and 31P-162 MHz) were
recorded using a 400 or 500-MHz spectrometer in CDCl3
(unless stated otherwise) with shifts referenced to SiMe4 (δ = 0)
or 85% H3PO4 (δ = 0). IR spectra were recorded on an FTIR
spectrophotometer. Melting points were determined by using a
local hot-stage melting point apparatus and are uncorrected.
Elemental analyses were carried out on a CHN analyzer. Mass
spectra were recorded using GCMS or LCMS instruments. High
resolution mass spectra (HR-MS) were performed using a
Bruker MaXis mass spectrometer (Bruker Daltonik GmbH,
Bremen, Germany) with ESI-QTOF-II method. Single crystal
X-ray diffraction was collected on OXFORD diffractometer by
using Mo–Ka (l = 0.71073 Å) radiation. The structure was
solved and refined by standard methods [9b–d]. The
allenylphosphonates and allenylphosphine oxide were prepared
by literature procedures [11]. Salicyl N-thiophosphinyl imines
1a–b were synthesized by the reported method [6a].
General procedure for the formation of chromans. To a
25-mL round–bottom flask containing allene 2a–e/5 (0.2–0.5 mmol)
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Vol 51
Scheme 2. Synthesis of various phosphono/phosphinoyl-chromans (cf. Table 2).
Table 2
31P NMR data and isolated yields of the compounds 3a–j and 6a–b.
δ(P)
Entry
Reactant
Product
E
Z
Yield %a (E:Z)
1
2
3
4
5
6
7
8
1a + 2a
1a + 2b
1a + 2c
1a + 2d
1a + 2e
1b + 2a
1b + 2b
1b + 2c
1b + 2d
1b + 2e
1a + 5
3a
3b
3c
3d
3e
3f
3g
3h
3i
14.5; 59.1
14.7; 59.1
14.8; 59.1
14.4; 59.1
11.0, 59.0
14.1; 59.0
14.3; 59.0
14.3; 59.0
14.0; 59.2
9.3, 10.2
10.4; 59.3
10.7; 59.3
10.8; 59.3
10.8; 59.2
10.1, 59.9
10.0; 59.5
10.3; 59.5
10.3; 59.4
9.5; 59.5
70 (17:53)
75 (26:49)
67 (23:44)
76 (21:55)
83b
61 (26:35)
62 (17:45)
57 (24:33)
62 (17:45)
78b
9
10
11
3j
6a
59.3, 60.2
24.0; 58.9
28.6; 58.1
41c
aIsolated yields of the pure compounds.
bIsomers were not separated.
cZ-isomer was only separated.
and salicyl N-thiophosphinyl imine (1a) or (1b) (0.22–0.55 mmol)
was added THF (0.1 M with respect to allene, 2.5–5.0 mL). The
contents were stirred at RT for 5 min. To this solution, P(n-Bu)
column chromatography (hexane/EtOAc; 1.5:1) to obtain the
pure product. Compounds 3a–j and 6a–b were prepared by this
procedure. Both Z and E isomers were formed in most cases.
Details on the combined yield of Z and E isomers are given in
Table 2 and in the succeeding discussion.
(0.04–0.1 mmol) was added, and the round-bottom flask was
3
sealed after flushing three times with N2. The reaction mixture
was stirred at 60°C for 12 h. After that, the solvent was
removed by rotary evaporator and the residue subjected to
Compound (E)-3a (higher Rf). Yield: 0.210 g (70%, E+Z);
0.051 g (E, isolated, 17%) (using 0.50 mmol of allene 2a). Mp:
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226–232°C. IR (KBr): 3189, 1630, 1482, 1258, 1231, 1057,
835 cmꢀ1. 1H NMR: δ 0.65 (s, 3H, CH3), 0.98 (s, 3H, CH3), 3.02–
OCHAHB), 3.95–4.06 (m, 3H, NH + OCH2), 4.73–4.80 (m, 1H,
CHNH), 6.63 (d, 3J(H–H) = 8.0 Hz, 1H, Ar-H), 6.84 (dd →t, 3J(H-
H) ~ 7.4 Hz, 1H, Ar-H), 7.05 (dd →t, 3J(H-H) ~ 7.8 Hz, 1H, Ar-H),
7.27–7.41 (m, 8H, Ar-H), 7.51–7.55 (m, 4H, Ar-H), 7.92–7.97 (m,
2H, Ar-H), 8.14–8.19 (m, 2H, Ar-H). 13C NMR (125 MHz,
CDCl3): δ 21.2, 21.7, 32.4 (d, J(P-C) = 6.3 Hz, C(CH3)2), 33.5
(dd, J(P-C) ~ 7.3 Hz, 1.6 Hz, CH2), 45.4 (NHCH), 75.4 (d, J(P-
C) = 5.9 Hz, OCH2(A)), 75.5 (d, J(P-C) = 6.3 Hz, OCH2(B)),
109.3 (d, 1J(P-C) = 195.6 Hz, PC = C), 116.4, 122.9, 124.5,
127.4 (d, J(P-C) = 1.6 Hz), 128.1, 128.3 (d, J(P-C) = 13.0 Hz),
128.7 (d, J(P-C) = 13.0 Hz), 129.5 (d, J(P-C) = 28.3 Hz), 130.7
(d, J(P-C) = 4.6 Hz), 131.5 (d, J(P-C) = 2.9 Hz), 131.7 (d, J(P-
C) = 11.1 Hz), 131.8 (d, J(P-C) = 2.8 Hz), 132.0 (d, J(P-
C) = 11.5 Hz), 133.9 (d, J(P-C) = 4.8 Hz), 134.0 (d, J(P-
C) = 22.9 Hz), 134.8 (d, J(P-C) = 25.0 Hz), 151.3, 161.0, 161.1.
31P NMR: δ 14.5 and 59.1. LC-MS: m/z 602 [M + 1]+. Anal.
Calcd. for C33H33NO4P2S: C, 65.88; H, 5.53; N, 2.33. Found:
C, 65.76; H, 5.61; N, 2.30.
3
3.14 (m, 2H, ¼CCH2), 3.48 (dd → t, J(P-H) = 2J(H-H) = 12.2 Hz,
1H, OCHAHB), 3.62 (dd →t, 3J(P-H) = 2J(H-H) ~ 12.0 Hz, 1H,
Figure 1. 1H NMR spectra in the region δ 2.0–5.0 for phosphono-
chromans: (a) (E)-3a and (b) (Z)-3a.
Compound (Z)-3a (lower Rf). Yield: 0.210 g (70%, E + Z);
0.051 g (Z, isolated, 53%). Mp: 188–190°C. IR (KBr): 3069,
1
2926, 1645, 1460, 1226, 1055, 826 cmꢀ1. H NMR (500 MHz):
δ 0.82 (s, 3H, CH3), 1.20 (s, 3H, CH3), 2.78–2.88 (m, 2H,
CCH2), 3.11–3.15 (m, 1H, NH), 3.53–3.56 (m, 1H, OCHAHB),
3.75–4.01 (m, 3H, OCHAHB + OCH2), 4.70–4.77 (m, 1H,
CHNH), 6.97–7.00 (m, 1H, Ar-H), 7.08 (d, 3J(H-H) = 8.0 Hz,
1H, Ar-H), 7.24–7.48 (m, 13H, Ar H), 7.71–7.75 (m, 2H, Ar
H), 7.82–7.86 (m, 2H, Ar H). 13C NMR (125 MHz): δ 21.1,
22.0, 32.4 (d, J(P-C) = 6.0 Hz, C(CH3)2), 33.4 (dd,
J
(P-C) ~ 10.2 Hz, J(P-C) ~ 4.2 Hz,CH2), 44.9 (NHCH), 76.0 (d, J
2
(P-C) = 6.5 Hz, OCH2(A)), 76.1 (d, J(P-C) = 6.1 Hz, OCH2(B)),
1
109.1 (d, J(P-C) = 173.4 Hz, PC = C), 117.0, 123.2, 124.3 (d, J
(P-C) = 4.5 Hz), 127.9, 128.4 (d, J(P-C) = 2.5 Hz), 128.5 (d, J
(P-C) = 2.4 Hz), 128.7, 128.9, 129.7, 130.8 (d, J(P-C) = 4.8 Hz),
131.5 (d, J(P-C) = 4.3 Hz), 131.6 (d, J(P-C) = 4.4 Hz), 131.7 (d,
J(P-C) = 2.8 Hz), 131.8 (d, J(P-C) = 2.8 Hz), 133.9, 134.0 (d, J
(P-C) = 22.5 Hz), 134.8 (d, J(P-C) = 28.0 Hz), 151.4, 160.2. 31P
NMR: δ 10.4 and 59.3. LC-MS: m/z 602 [M + 1]+. Anal. Calcd.
for C33H33NO4P2S: C, 65.88; H, 5.53; N, 2.33. Found: C,
65.78; H, 5.49; N, 2.26.
Compound (E)-3b (higher Rf). Yield: 0.231 g (75%, E + Z);
0.080 g (E, isolated, 26%) (using 0.5 mmol of allene 2b). Mp:
196–198°C. IR (KBr): 3239, 1626, 1572, 1437, 1240, 1107,
810 cmꢀ1 1H NMR: δ 0.68 (s, 3H, CH3), 1.00 (s, 3H, CH3),
.
2.39 (s, 3H, C6H4CH3), 3.04–3.13 (m, 2H, CCH2), 3.47
(dd → t, 3J(P-H) = 2J(H-H) = 11.6 Hz, 1H, OCHAHB), 3.62
3
(dd → t, J(P-H) = 2J(H-H) ~ 11.6 Hz, 1H, OCHAHB), 3.90–4.02
(m, 3H, OCH2 + NH), 4.73–4.80 (m, 1H, CHNH), 6.66 (d, 3J
3
(H-H) = 8.4 Hz, 1H, Ar-H), 6.83 (dd → t, J(H-H) = 7.6 Hz, 1H,
Ar-H), 7.05 (dd → t, 3J(H-H) ~ 7.0 Hz, 1H, Ar-H), 7.20–7.40
(m, 7H, Ar-H), 7.50–7.54 (m, 4H, Ar-H), 7.91–7.97 (m, 2H,
Ar-H), 8.13–8.18 (m, 2H, Ar-H). 13C NMR (125 MHz): δ 21.3,
21.4 (s, C6H4CH3), 21.8, 32.4 (d, J(P-C) = 5.8 Hz, C(CH3)2),
Figure 2. Molecular structure of compound (Z)-3a. Selected bond lengths
[Å] with esds in parentheses. O(4)–C(7) 1.365(6), C(8)–C(9) 1.516(8), N
(1)–C(9) 1.472(7), C(7)–C(8) 1.488(8), C(6)–C(7) 1.346(8), P(1)–C(6)
1.800(6) and C(6)–C(16) 1.504(7).
Scheme 3. Formation of chromene 4 via hydrazone 7.
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33.6 (d, J(P-C) ~ 7.4 Hz, CH2), 45.4 (s, NHCH), 75.5 (d, J
(P-C) = 6.3 Hz, OCH2(A)), 75.6 (d, J(P-C) = 6.3 Hz, OCH2(B)),
109.2 (d, 1J(P-C) = 192.9 Hz, PC = C), 116.5, 122.8, 124.5,
128.3 (d, J(P-C) = 13.0 Hz), 128.7 (d, J(P-C) = 13.3 Hz), 128.9,
129.5 (d, J(P-C) = 29.4 Hz), 130.5 (d, J(P-C) = 5.0 Hz), 130.6 (d,
CHNH), 6.91–7.08 (m, 4H, Ar-H), 7.21–7.44 (m, 10H, Ar-H),
7.70–7.85 (m, 4H, Ar H). 13C NMR: δ 21.0, 22.0, 32.3 (d, J(P–
C) = 5.6 Hz, C(CH3)2), 33.3 (~d, J(P-C) ~ 7.4 Hz, CH2), 44.9
(NHCH), 55.3 (OCH3), 76.0 (OCH2), 108.5 (d, 1J
(P-C) = 173.1 Hz, PC = C), 114.1, 116.9, 123.0, 124.3, 125.8,
128.4, 128.5, 128.7, 129.6, 131.5, 131.6, 131.7, 131.8, 133.9 (d,
J(P-C) = 32.1 Hz), 134.7 (d, J(P-C) = 32.1 Hz), 151.4, 159.2,
159.8. 31P NMR: δ 10.8 and 59.3. LC-MS: m/z 632 [M + 1]+.
Anal. Calcd. for C34H35NO5P2S: C, 64.65; H, 5.58; N, 2.22.
Found: C, 64.58; H, 5.51; N, 2.26.
J(P-C) = 5.1 Hz), 131.5 (d, J(P-C) = 2.9 Hz), 131.7 (d,
(P-C) = 11.0 Hz), 131.8 (d, J(P-C) = 2.8 Hz), 132.0 (d,
(P-C) = 11.1 Hz), 134.1 (d, J(P-C) = 19.8 Hz), 134.9 (d,
J
J
J
(P-C) = 21.0 Hz), 137.0 (d, J(P-C) = 1.9 Hz), 151.4, 160.5, 160.7.
31P NMR: δ 14.7 and 59.1. LC-MS: m/z 616 [M + 1]+. Anal.
Calcd. for C34H35NO4P2S: C, 66.33; H, 5.73; N, 2.28. Found:
C, 66.15; H, 5.81; N, 2.32.
Compound (E)-3d (higher Rf). Yield: 0.097 g (76%, E + Z);
0.027 g (E, isolated, 21%) (using 0.2 mmol of allene 2d). Mp:
188–192°C. IR (KBr): 3181, 3058, 1630, 1597, 1485, 1088,
Compound (Z)-3b (lower Rf). Yield: 0.231 g (75%, E + Z);
0.151 g (Z, isolated, 49%). Mp: 204–210°C. IR (KBr):3214,
1
1006 cmꢀ1. H NMR: δ 0.70 (s, 3H, CH3), 0.96 (s, 3H, CH3),
2920, 1626, 1597, 1455, 1238, 1059, 831 cmꢀ1
.
1H NMR: δ
2.98–3.00 (m, 1H, CHCHAHB), 3.13–3.16 (m, 1H, CHCHAHB),
0.81 (s, 3H, CH3), 1.20 (s, 3H, CH3), 2.44 (s, 3H, C6H4CH3),
2.74–2.88 (m, 2H, CHCH2), 3.11–3.14 (m, 1H, NH), 3.53–3.56
(m, 1H, OCHAHB), 3.73–4.03 (m, 3H, OCH2 + OCHAHB),
4.72–4.77 (m, 1H, CHNH), 6.96–7.44 (m, 14H, Ar-H), 7.70–
7.71 (m, 2H, Ar-H), 7.80–7.83 (m, 2H, Ar-H). 13C NMR
(125 MHz): δ 21.0, 21.3 (s, C6H4CH3), 22.0, 32.3 (d, J(P-
C) = 6.1 Hz, C(CH3)2), 33.5 (dd, 3J(P-C) = 4.3 Hz, 10.3 Hz,
CH2), 44.9 (s, NHCH), 76.0 (d, J(P-C) = 7.5 Hz, OCH2(A)),
76.1 (d, J(P-C) = 6.6 Hz, OCH2(B)), 108.8 (d, 1J
(P-C) = 172.3 Hz, PC = C), 116.9, 123.0, 124.3, 128.3 (d, J
(P-C) = 2.6 Hz), 128.4 (d, J(P-C) = 2.9 Hz), 128.7, 129.4, 129.6,
130.5 (d, J(P-C) = 4.8 Hz), 130.7 (d, J(P-C) = 6.4 Hz), 131.46,
3.51 (dd → t, 3J(P-H) = 2J(H-H) ~ 12.2 Hz, 1H, OCHAHB), 3.63
3
(dd → t, J(P-H) = 2J(H-H) ~ 12.6 Hz, 1H, OCHAHB), 3.95–4.11
(m, 3H, OCH2 + NH), 4.75–4.76 (m, 1H, CHNH), 6.64 (d, 3J
(H–H) = 8.0 Hz, 1H, Ar-H), 6.84–6.88 (m, 1H, Ar-H), 7.05–7.09
(m, 1H, Ar-H), 7.26–7.55 (m, 11H, Ar-H), 7.91–7.96 (m, 2H,
Ar-H), 8.13–8.16 (m, 2H, Ar-H). 13C NMR (125 MHz): δ 21.4,
21.6, 32.4 (d, 3J(P-C) = 5.9 Hz, C(CH3)2), 33.4 (d, J(P-
C) = 7.3 Hz, CH2), 45.3 (NHCH), 75.3 (d, J(P-C) = 6.1 Hz,
OCH2(A)), 75.4 (d, J(P-C) = 5.9 Hz, OCH2(B)), 107.8 (d, 1J
(P-C) = 197.0 Hz, PC = C), 116.4, 123.1, 124.5 (d, J(P-
C) = 2.8 Hz), 128.3, 128.4, 128.8 (d, J(P-C) = 13.1 Hz), 129.5 (d,
J(P-C) = 4.3 Hz), 131.6 (d, J(P-C) = 2.6 Hz), 131.7 (d,
(P-C) = 17.5 Hz), 131.9 (d, J(P-C) = 2.3 Hz), 132.0 (d,
(P-C) = 11.4 Hz), 132.1 (d, J(P-C) = 4.6 Hz), 132.4 (d,
(P-C) = 5.1 Hz), 133.4 (d, J(P-C) = 2.1 Hz), 133.9 (d,
J
J
J
J
131.49, 131.6 (d, J(P-C) = 3.3 Hz), 131.7, 133.9 (d,
J
(P-C) = 32.3 Hz), 134.7 (d, J(P-C) = 35.5 Hz), 137.4, 151.4,
159.7. 31P NMR: δ 10.7 and 59.3. LC-MS: m/z 616 [M + 1]+.
Anal. Calcd. for C34H35NO4P2S: C, 66.33; H, 5.73; N, 2.28.
Found: C, 66.48; H, 5.70; N, 2.21.
(P-C) = 24.0 Hz), 134.8 (d, J(P-C) = 24.8 Hz), 151.2, 161.6,
161.8. 31P NMR: δ 14.4 and 59.2. LC-MS: m/z 635 [M ꢀ 1]+
and 637 [M + 1]+. Anal. Calcd. for C33H32ClNO4P2S: C, 62.31;
H, 5.07; N, 2.20. Found: C, 62.21; H, 5.15; N, 2.26.
Compound (E)-3c (higher Rf). Yield: 0.212 g (67%, E + Z);
0.049 g (E, isolated, 23%) (using 0.5 mmol of allene 2c). Mp:
180–184°C. IR (KBr): 3478, 3198, 1628, 1510, 1233, 1058,
Compound (Z)-3d (lower Rf). Yield: 0.097 g (76%, E + Z);
0.070 g (Z, isolated, 55%). Mp: 176–180°C. IR (KBr): 3202,
833 cmꢀ1 1H NMR: δ 0.69 (s, 3H, CH3), 1.00 (s, 3H, CH3),
.
3.04–3.13 (m, 2H, CCH2), 3.49 (dd → t, 3J(P-H) = 2J
(H-H) = 11.6 Hz, 1H, OCHAHB), 3.63 (dd → t, 3J(P-H) ~ 2J
(H-H) ~ 12.0 Hz, 1H, OCHAHB), 3.86 (s, 3H, C6H4OCH3),
3.93–4.04 (m, 3H, OCH2 + NH), 4.75–4.76 (m, 1H, CHNH),
3058, 1630, 1483, 1242, 1059, 1009, 791 cmꢀ1 1H NMR: δ
.
0.83 (s, 3H, CH3), 1.18 (s, 3H, CH3), 2.76–2.77 (m, 2H,
CHCH2), 3.05–3.09 (m, 1H, NH), 3.53–3.58 (m, 1H,
OCHAHB), 3.79–4.06 (m, 3H, OCHAHB + OCH2), 4.71–4.76
(m, 1H, CHNH), 7.00–7.08 (m, 2H, Ar-H), 7.23–7.48 (m, 12H,
Ar-H), 7.72–7.77 (m, 2H, Ar-H), 7.81–7.86 (m, 2H, Ar-H). 13C
NMR: δ 21.2, 22.0, 32.4 (d, J(P-C) = 6.5 Hz, C(CH3)2), 33.5
(dd, J(P-C) ~ 10.4 Hz, J(P-C) ~ 3.4 Hz, CH2), 45.0 (NHCH),
76.0 (d, J(P-C) = 6.3 Hz, OCH2(A)), 76.1 (d, J(P-C) = .6.1 Hz,
3
6.66 (d, J(H-H) = 8.0 Hz, 1H, Ar-H), 6.82–6.94 (m, 3H, Ar-H),
7.04–7.07 (m, 1H, Ar-H), 7.27–7.56 (m, 9H, Ar-H), 7.92–7.97
(m, 2H, Ar-H), 8.15–8.17 (m, 2H, Ar-H). 13C NMR: δ 21.3,
21.7, 32.4 (d, J(P-C) = 5.8 Hz, C(CH3)2), 33.5 (d,
J
(P-C) ~ 6.0 Hz, CH2), 45.4 (NHCH), 55.3 (OCH3), 75.4 (d, J
(P-C) = 6.3 Hz, OCH2(A)), 75.5 (d, J(P-C) = 6.3 Hz, OCH2(B)),
108.8 (d, 1J(P-C) = 195.4 Hz, PC = C), 113.6, 116.4, 122.8,
124.5, (d, J(P-C) = 2.1 Hz), 125.8 (d, J(P-C) = 4.9 Hz), 128.3 (d,
J(P-C) = 13.3 Hz), 128.5 (d, J(P-C) = 13.3 Hz), 128.7 (d, J
1
OCH2(B)), 107.9 (d, J(P-C) = 174.9 Hz, PC = C), 117.1, 123.4,
124.4 (d, J(P-C) = 5.4 Hz), 128.5, 128.51, 128.57, 128.6, 129.0,
129.8, 131.5 (d, J(P-C) = 2.3 Hz), 131.6 (d, J(P-C) = 1.6 Hz),
131.9, 132.1 (d, J(P-C) = 4.8 Hz), 132.5 (d, J(P-C) = 6.6 Hz),
133.9 (d, J(P-C) = 16.0 Hz), 134.0, 134.7 (d, J(P-C) = 18.4 Hz),
151.4, 160.5. 31P NMR: δ 10.1 and 59.3. LC-MS: m/z 634
[M ꢀ 2]+ and 636 [M]+. Anal. Calcd. for C33H32ClNO4P2S: C,
62.31; H, 5.07; N, 2.20. Found: C, 62.21; H, 5.15; N, 2.28.
(P-C) = 13.1 Hz), 129.5 (d, J(P-C) = 28.8 Hz), 131.3 (d,
J
(P-C) = 11.5 Hz), 131.5 (d, J(P-C) = 2.5 Hz), 131.7, 131.8, 132.0
(d, J(P-C) = 11.4 Hz), 134.1 (d, J(P-C) = 22.4 Hz), 134.9 (d, J
(P-C) = 23.4 Hz), 151.4, 159.0, 160.7. 31P NMR: δ 14.8 and
59.1. LC-MS: m/z 632 [M + 1]+. Anal. Calcd. for
C34H35NO5P2S: C, 64.65; H, 5.58; N, 2.22. Found: C, 64.53;
H, 5.61; N, 2.27.
Compound (E + Z)-3e.
0.3 mmol of allene 2e). Mp: 210–214°C. IR (KBr): 3212, 3058,
1628, 1601, 1453, 1289, 1244, 1060 cmꢀ1 1H NMR: (E/
Yield: 0.16 g (83%, E + Z) (using
.
Compound (Z)-3c (lower Rf). Yield: 0.212 g (67%, E + Z);
0.093 g (Z, isolated, 44%). Mp: 184–188°C. IR (KBr): 3191,
Z ~ 1:1) δ 0.70, 0.79 and 1.10 (3 s, 12H, CH3), 2.51–2.66 (m,
4H), 3.30–3.50 (m, 4H), 3.68–3.76 (m, 2H), 3.93–4.14 (m, 4H),
4.61–4.68 (m, 2H, CHNH), 6.95–7.00 (m, 4H, Ar-H), 7.16–
1
2963, 1628, 1510, 1244, 1061, 772 cmꢀ1. H NMR: δ 0.81 (s,
3
3H, CH3), 1.20 (s, 3H, CH3), 2.72–2.89 (m, 2H, CHCH2),
3.13–3.17 (m, 1H, NH), 3.52–3.56 (m, 1H, OCHAHB), 3.77–
4.04 (m, 6H, OCHAHB + OCH2 + OCH3), 4.72–4.78 (m, 1H,
7.82 (m, 37H, Ar-H), 8.34 (d, J(H-H) = 8.4 Hz, 1H, Ar-H). 13C
NMR: (E + Z) δ 21.2, 21.3, 21.9, 32.4 (d, J(P-C) = 6.0 Hz, C
(CH3)2), 32.5 (d, J(P-C) = 6.2 Hz, C(CH3)2), 33.5 (dd, J(P-
Journal of Heterocyclic Chemistry
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Phosphine Catalyzed Synthesis of Phosphono-chromans
765
C) ~ 10.2 Hz, J(P-C) ~ 5.4 Hz, CH2), 33.8 (dd, J(P-C) ~ 10.7 Hz, J
(P-C) ~ 4.2 Hz,CH2), 44.3 (d, J(P-C) = 4.5 Hz, -NHCH), 44.7 (d, J
(P-C) = 4.9 Hz, -NHCH), 75.8 (d, J(P-C) = 3.6 Hz, OCH21(A)),
76.0 (d, J(P-C) = .6.0 Hz, OCH2(B)), 76.3, 76.4, 106.4 (d, J(P-
C) = 176.0 Hz, PC = C), 107.5 (d, 1J(P-C) = 177.0 Hz, PC = C),
117.0, 117.1, 123.9 (d, J(P-C) = 28.0 Hz), 125.0, 125.5 (d, J(P-
C) = 13.0 Hz), 126.2, 126.4, 126.6, 126.9, 128.1, 128.30, 128.32,
128.40, 128.44, 128.7, 128.9, 129.0, 129.1, 129.20, 129.24,
129.3, 129.6, 129.7, 130.7, 130.8, 131.4, 131.5, 131.7, 131.9,
132.8, 133.3, 133.6, 133.8, 134.0, 134.3, 134.9 (d, J(P-
C) = 19.0 Hz), 151.3, 151.4, 161.2, 161.3 (the spectrum was
complicated because of the peaks for both the isomers). 31P
NMR: δ 10.1, 11.0 and 59.0, 59.9. LC-MS: m/z 650 [M ꢀ 1]+.
Anal. Calcd. for C37H35NO4P2S: C, 68.19; H, 5.41; N, 2.15.
Found: C, 68.32; H, 5.38; N, 2.21.
Compound (E)-3f (higher Rf). Yield: 0.194 g (61%, E + Z);
0.083g (E, isolated, 26%) (using 0.5 mmol of allene 2a). Mp:
260–264°C. IR (KBr): 3229, 1624, 1595, 1472, 1250, 1057, 837,
787 cmꢀ1. 1H NMR (500 MHz): δ 0.66 (s, 3H, CH3), 0.99 (s, 3H,
CH3), 3.08–3.12 (m, 2H, CHCH2), 3.46–3.51 (m, 1H, OCHAHB),
3.62–3.67 (m, 1H, OCHAHB), 3.97–4.05 (m, 3H, NH + OCH2),
4.73–4.75 (m, 1H, CHNH), 6.57 (d, 3J(H-H) = 9.0 Hz, 1H, Ar-H),
6.97–7.00 (m, 1H, Ar-H), 7.32–7.54 (m, 12H, Ar-H), 7.93–7.97
(m, 2H, Ar-H), 8.12–8.17 (m, 2H, Ar-H). 13C NMR (125 MHz): δ
21.2, 21.7, 32.3 (d, J(P-C) = 6.1 Hz, C(CH3)2), 33.0 (d, J(P-
C)= 8.0 Hz, CH2), 45.1 (NHCH), 75.5 (d, J(P-C)= 6.1Hz, OCH2
(A)), 75.6 (d, J(P-C) = 6.1 Hz, OCH2(B)), 110.0 (d, 1J(P-
C)= 194.6Hz, PC = C), 117.8, 125.8, 127.6 (d, J(P-C) = 27.8 Hz),
128.2, 128.3 (d, J(P-C)= 13.3 Hz), 129.4 (d, J(P-C) = 17.5 Hz),
130.6 (d, J(P-C)= 4.6 Hz), 131.6, 131.70, 131.72, 131.8, 131.9,
133.6 (d, J(P-C) = 4.8 Hz), 133.8 (d, J(P-C)= 12.5Hz), 134.6 (d, J
(P-C)= 10.6 Hz), 149.9, 160.2, 160.4. 31P NMR: δ 14.1 and 59.0.
LC-MS: m/z 636 [M]+ and 638 [M+ 2]+. Anal. Calcd. for
C33H32ClNO4P2S: C, 62.31; H, 5.07; N, 2.20. Found: C, 62.21;
H, 5.13; N, 2.27.
3J(H-H) = 8.8 Hz, Ar-H), 6.95–6.98 (m, 1H, Ar-H), 7.18–7.51
(m, 11H, Ar-H), 7.90–7.96 (m, 2H, Ar-H), 8.10–8.14 (m, 2H,
Ar-H). 13C NMR (125 MHz): δ 21.2, 21.3 (s, C6H4CH3), 21.7,
32.3 (d, J(P-C) = 6.0 Hz, C(CH3)2), 33.1 (d, J(P-C) ~ 6.1 Hz,
CH2), 45.1 (NHCH), 75.5 (d, J(P-C) = 6.0 Hz, OCH2(A)), 75.6
(d, 3J(P-C) = 6.1 Hz, OCH2(B)), 109.8 (d, 1J(P-C) = 193.1 Hz,
PC = C), 117.7, 125.9, 127.6, 128.2 (d, J(P-C) = 13.1 Hz), 128.7
(d, J(P-C) = 13.1 Hz), 128.9, 129.3 (d, J(P-C) = 17.3 Hz), 130.26
(d, J(P-C) = 4.6 Hz), 130.32, 131.6 (d, J(P-C) = 2.1 Hz), 131.70,
131.74, 131.8, 133.8 (d, J(P-C) = 17.5 Hz), 134.6 (d,
J
(P-C) = 15.9 Hz), 137.1, 149.9, 159.7. 31P NMR: δ 14.3 and
59.0. LC-MS: m/z 650 [M]+ and 652 [M + 2]+. Anal. Calcd. for
C34H34ClNO4P2S: C, 62.82; H, 5.27; N, 2.15. Found: C, 62.75;
H, 5.15; N, 2.21.
Compound (Z)-3 g (lower Rf). Yield: 0.201 g (62%, E + Z);
0.146 g (Z, isolated, 45%). Mp: 230–234°C. IR (KBr): 3208,
2963, 1630, 1597, 1474, 1254, 1061, 720 cmꢀ1 1H NMR
.
(500 MHz): δ 0.80 (s, 3H, CH3), 1.19 (s, 3H, CH3), 2.44 (s, 3H,
C6H4CH3), 2.72–2.87 (m, 2H, CHCH2), 3.26–3.30 (m, 5H,
OCH2 + NH), 4.69–4.75 (m, 1H, CHNH), 6.98–7.00 (m, 1H,
Ar-H), 7.14–7.53 (m, 12H, Ar-H), 7.67–7.73 (m, 2H, Ar-H),
7.80–7.85 (m, 2H, Ar-H). 13C NMR (125 MHz): δ 21.0, 21.4,
22.0, 32.4 (d, J(P-C) = 6.1 Hz, C(CH3)2), 33.0 (d,
J
(P-C) = 14.4 Hz, CH2), 44.7 (NHCH), 76.1 (OCH2(A)), 76.2
1
(OCH2(B)), 109.9 (d, J(P-C) = 171.1 Hz, PC = C), 118.4, 125.7
(d, J(P-C) = 4.4 Hz), 128.0, 128.5 (d, J(P-C) = 1.3 Hz), 128.6,
128.7, 129.5, 129.6, 130.5 (d, J(P-C) = 4.9 Hz), 130.6, 131.5 (d,
J(P-C) = 11.5 Hz), 131.7 (d, J(P-C) = 11.1 Hz), 131.8 (d, J
(P-C) = 2.9 Hz), 132.0 (d, J(P-C) = 2.9 Hz), 133.8 (d,
J
(P-C) = 67.5 Hz), 134.6 (d, J(P-C) = 68.5 Hz), 137.9, 150.1,
159.2. 31P NMR: δ 10.3 and 59.5. LC-MS: m/z 650 [M]+ and
652 [M + 2]+. Anal. Calcd. for C34H34ClNO4P2S: C, 62.82; H,
5.27; N, 2.15. Found: C, 62.71; H, 5.35; N, 2.19.
Compound (E)-3 h (higher Rf).
Yield: 0.190 g (57%,
E + Z); 0.080 g (E, isolated, 24%) (using 0.5 mmol of allene 2c).
Mp: 208–210°C. IR (KBr): 3229, 2481, 1624, 1596, 1474,
Compound (Z)-3f (lower Rf). Yield: 0.194 g (61%, E + Z)
0.111 g (Z, isolated, 35%). Mp: 236–238°C. IR (KBr): 3223,
1246, 1057, 839 cmꢀ1 1H NMR (500 MHz): δ 0.69 (s, 3H,
.
1
1628, 1476, 1248, 1105, 1060, 828 cmꢀ1. H NMR: δ 0.80 (s,
CH3), 1.00 (s, 3H, CH3), 3.08–3.23 (m, 2H, CHCH2), 3.47
(dd → t, 3J(P–H) ~ 2J(H-H) ~ 12.5 Hz, 1H, OCHAHB), 3.64
(dd → t, 3J(P-H) ~ 2J(H-H) ~ 12.5 Hz, 1H, OCHAHB), 3.85 (s,
3H, OCH3), 3.91–4.03 (m, 3H, OCH2 + NH), 4.73–4.76 (m, 1H,
CHNH), 6.59 (d, 3J(H-H) = 5.0 Hz, 1H, Ar-H), 6.92–6.99 (m,
3H, Ar-H), 7.25–7.52 (m, 9H, Ar H), 7.92–7.96 (m, 2H, Ar H),
8.10–8.15 (m, 2H, Ar-H). 13C NMR (125 MHz): δ 21.1, 22.0,
32.4 (d, J(P-C) = 6.3 Hz, C(CH3)2), 33.0 (d, J(P-C) ~ 10.0 Hz,
CH2), 44.7 (NHCH), 55.4 (C6H4OCH3), 76.10 (OCH2(A)),
3H, CH3), 1.18 (s, 3H, CH3), 2.74–2.85 (m, 2H, CHCH2),
3.17–4.04 (m, 5H, OCH2 + NH), 4.68–4.73 (m, 1H, CHNH),
7.00–7.01 (m, 1H, Ar-H), 7.16–7.18 (m, 1H, Ar-H), 7.27–7.46
(m, 12H, Ar-H), 7.68–7.74 (m, 2H, Ar-H), 7.81–7.86 (m, 2H,
Ar-H). 13C NMR: δ 21.1, 22.0, 32.4 (d, J(P-C) = 6.1 Hz, C(CH3)
2), 33.1 (dd, J(P-C) ~ 10.1 Hz, J(P-C) ~ 4.2 Hz, CH2), 44.7
(NHCH), 76.05 (d, J = 7.0 Hz, OCH2(A)), 76.10 (d, J = 6.6 Hz,
OCH2(B)), 110.0 (d, 1J(P-C) = 172.6 Hz, PC = C), 118.4, 125.8
(d, J(P-C) = 4.8 Hz), 128.0, 128.5 (d, J(P-C) = 1.5 Hz), 128.6 (d,
J(P-C) = 1.8 Hz), 128.8, 129.6, 130.7 (d, J(P-C) = 4.8 Hz), 131.4,
131.5, 131.6, 131.7, 131.8 (d, J(P-C) = 2.9 Hz), 132.0 (d, J
1
76.13 (OCH2(B)), 109.3 (d, J(P-C) = 172.5 Hz, PC = C), 114.2,
118.3, 125.6 (d, J(P-C) = 6.3 Hz), 125.8 (d, J(P-C) = 5.0 Hz),
127.9, 128.5, 128.6, 129.6, 131.4, 131.5, 131.6, 131.70, 131.74,
(P-C) = 3.0 Hz), 133.68 (d, J(P-C) = 6.1 Hz), 133.69 (d,
J
131.8, 131.9, 133.8 (d, J(P-C) = 13.7 Hz), 134.6 (d, J
(P-C) = 57.8 Hz), 134.5 (d, J(P-C) = 54.1 Hz), 150.0, 159.4. 31P
NMR: δ 10.0 and 59.5. LC-MS: m/z 635 [M ꢀ 1]+and 637
[M + 1]+. Anal. Calcd. for C33H32ClNO4P2S: C, 62.31; H, 5.07;
N, 2.20. Found: C, 62.28; H, 5.11; N, 2.15.
(P-C) = 12.5 Hz), 150.0, 159.3. 31P NMR: δ 14.3 and 59.0.
Anal. Calcd. for C34H34ClNO5P2S: C, 61.31; H, 5.14; N, 2.10.
Found: C, 61.25; H, 5.19; N, 2.18.
Compound (Z)-3 h (lower Rf). Yield: 0.190 g (57%, E + Z);
0.110 g (Z, isolated, 33%). Mp: 228–232°C. IR (KBr): 3235,
Compound (E)-3 g (higher Rf).
Yield: 0.201 g (62%,
1
E + Z); 0.055 g (E, isolated, 17%) (using 0.5 mmol of allene 2b).
Mp: 216–220°C. IR (KBr): 3169, 1624, 1597, 1474, 1250,
1632, 1601, 1439, 1057, 1009, 756 cmꢀ1. H NMR (500 MHz):
δ 0.81 (s, 3H, CH3), 1.19 (s, 3H, CH3), 2.74–2.86 (m, 2H,
CHCH2), 3.22–3.26 (m, 1H, NH), 3.53 (dd, 3J(P-H) = 12.5 Hz,
2J(H-H) = 7.5 Hz, 1H, OCHAHB), 3.74–4.02 (m, 6H,
OCHAHB + OCH2 + C6H4OCH3), 4.70–4.75 (m, 1H, CHNH),
6.92–7.00 (m, 3H, Ar-H), 7.15–7.49 (m, 10H, Ar-H), 7.71–7.76
(m, 2H, Ar-H), 7.82–7.86 (m, 2H, Ar-H). 13C NMR (125 MHz):
1101, 716 cmꢀ1 1H NMR: δ 0.68 (s, 3H, CH3), 0.99 (s, 3H,
.
CH3), 2.39 (s, 3H, C6H4CH3), 3.05–3.12 (m, 2H, CHCH2), 3.46
(dd → t, 3J(P-H) = 2J(H-H) ~ 11.4 Hz, 1H, OCHAHB), 3.63
3
(dd → t, J(P-H) = 2J(H-H) ~ 11.4 Hz, 1H, OCHAHB), 3.90–4.04
(m, 3H, OCH2 + NH), 4.74–4.75 (m, 1H, CHNH), 6.57 (d, 1H,
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

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Vol 51
δ 21.2, 21.7, 32.3 (d, J(P-C) = 5.9 Hz, C(CH3)2), 33.1 (d, J
(P-C) ~ 6.9 Hz, CH2), 45.2 (NHCH), 55.3 (OCH3), 75.5 (d, J
(P-C) = 6.1 Hz, OCH2(A)), 75.6 (d, J(P-C) = 6.3 Hz, OCH2(B)),
109.4 (d, J(P-C) = 193.9 Hz, PC = C), 113.6, 117.7, 125.5 (d, J
(P-C) = 5.1 Hz), 125.9 (d, J(P-C) = 1.9 Hz), 127.6, 128.2 (d, J
(P-C) = 6.3 Hz, C(CH3)2), 33.2 (dd, J(P-C) ~ 10.1 Hz, J(P-C) ~ 5.6 Hz,
CH2) and 33.4 (dd, J(P-C) ~ 10.7 Hz, J(P-C) ~ 4.7 Hz, CH2), 44.2
(NHCH) and 44.5 (NHCH), 75.81 (d, J(P-C) = 5.9 Hz, OCH2(A)),
75.83 (d, J(P-C) = .6.0 Hz, OCH2(B)), 76.0 (d, J(P-C) = 6.1 Hz,
OCH2(A)), 76.4 (d, J(P-C) = 6.5 Hz, OCH2(B)), 107.3 (d, 1J
(P-C) = 176.3 Hz, PC = C) and 108.3 (d, 1J(P-C) = 176.8 Hz,
PC = C), 118.41, 118.43, 124.5, 125.3, 125.4, 125.5, 125.6,
126.2 (d, J(P-C) = 16.6 Hz), 126.6, 126.9, 127.0, 128.1, 128.2,
128.3, 128.40 128.41, 128.4, 128.5, 128.9, 129.0, 129.10, 129.11,
129.20, 129.23, 129.65, 129.67, 130.5 (d, J(P-C) = 5.6 Hz), 131.4
(d, J(P-C) = 11.1 Hz), 131.55, 131.57, 131.62, 131.64, 131.71,
131.73, 131.9, 132.6 (d, J(P-C) = 4.8 Hz), 133.1, 133.3, 133.4 (d, J
(P-C) = 2.5 Hz), 133.5, 133.9, 134.0 (d, J(P-C)= 5.5Hz), 134.1,
134.3, 134.8, 149.9, 150.0, 160.5, 160.6 (the spectrum was
complicated because of the peaks for both the isomers). 31P
NMR: δ 9.3, 10.2 and 59.3, 60.2. LC-MS: m/z 686 [M]+ and 688
[M+ 2]+. Anal. Calcd. for C37H34ClNO4P2S: C, 64.77; H, 4.99;
N, 2.04. Found: C, 64.85; H, 4.91; N, 2.12.
1
(P-C) = 12.9 Hz), 128.7 (d, J(P-C) = 12.9 Hz), 129.3 (d,
J
(P-C) = 16.6 Hz), 131.60, 131.63, 131.67, 131.8, 131.9, 133.8 (d,
J(P-C) = 14.1 Hz), 134.6 (d, J(P-C) = 12.5 Hz), 149.9, 158.9,
159.9, 160.2. 31P NMR: δ 10.3 and 59.4. LC-MS: m/z 666 [M]+
and 668 [M + 2]+. Anal. Calcd. for C34H34ClNO5P2S: C, 61.31;
H, 5.14; N, 2.10. Found: C, 61.35; H, 5.09; N, 2.18.
Compound (E)-3i (higher Rf). Yield: 0.208 g (62%, E + Z);
0.057 g (E, isolated, 17%) (using 0.5 mmol of allene 2d). Mp:
186–190°C. IR (KBr): 3200, 1628, 1474, 1250, 1059,
789 cmꢀ1 1H NMR: δ 0.70 (s, 3H, CH3), 0.96 (s, 3H, CH3),
.
3.06–3.14 (m, 2H, CHCH2), 3.50 (dd → t, 3J(P-H) = 2J
(H-H) ~ 12.7 Hz, 1H, OCHAHB), 3.64 (dd → t, 3J(P-H) = 2J
(H-H) ~ 12.7 Hz, 1H, OCHAHB), 3.95–4.12 (m, 3H,
OCH2 + NH), 4.70–4.77 (m, 1H, CHNH), 6.56 (d, 3J
(H-H) = 8.8 Hz, 1H, Ar-H), 6.98–7.00 (m, 1H, Ar-H), 7.26–7.52
(m, 11H, Ar-H), 7.90–7.96 (m, 2H, Ar-H), 8.08–8.14 (m, 2H, Ar-
H). 13C NMR: δ 21.4, 21.6, 32.4 (d, J(P-C)= 5.6Hz, C(CH3)2),
33.0 (dd → ~d, J(P-C) ~ 7.2 Hz, CH2), 45.0 (NHCH), 75.3 (d, J(P-
C)= 5.9 Hz, OCH2(A)), 75.5 (d, J(P-C) = 6.1 Hz, OCH2(B)), 108.4
(d, 1J(P-C) = 196.3 Hz, PC = C), 117.7, 125.9, 128.0, 128.3, 128.4,
128.8 (d, J(P-C)= 13.0Hz), 129.4 (d, J(P-C) = 3.8 Hz), 131.7,
131.8, 131.90, 131.94, 132.0, 132.1, 133.5 (d, J(P-C)= 9.7 Hz),
134.6 (d, J(P-C)= 7.4 Hz), 149.7, 155.9, 160.9, 161.2. 31P NMR:
δ 14.0 and 59.2. LC-MS: m/z 670 [M]+, 672 [M+ 2]+ and 674
[M+ 4]+. Anal. Calcd. for C33H31Cl2NO4P2S: C, 59.11; H, 4.66;
N, 2.09. Found: C, 59.23; H, 4.61; N, 2.15.
Compound (Z)-6a (higher Rf). Yield: 0.134 g (41%; using
0.5 mmol of allene 5). Mp: 248–250°C. IR (KBr): 3187, 3058,
1628, 1474, 1248, 1059, 791 cmꢀ1 1H NMR: δ 2.65–2.70 (br
.
d, 3J(H–H) ~ 12.0 Hz, 1H, CHCHA), 2.85–2.90 (dd, 3J
4
(H-H) ~ 14.8 Hz, J(P-H) = 4.1 Hz, 1H, CHCHB), 3.35–3.39 (dd,
4
3J(H-H) ~ 6.4 Hz, J(P-H) ~ 6.8 Hz, 1H, NH), 4.66–4.72 (m, 1H,
CHNH), 6.14 (d, 3J(H-H) = 7.6 Hz, 1H, Ar-H), 6.83–6.85 (m,
1H, Ar-H), 7.01–7.18 (m, 1H, Ar H), 7.23–7.46 (m, 18H, Ar-
H), 7.68–7.85 (m, 8H, Ar H). 13C NMR: δ 33.5 (dd → t, J
(P-C) ~ J(P-C) ~ 5.5 Hz, CH2), 44.8 (s, NHCH), 115.1 (d, 1J
(P-C) = 95.6 Hz, PC = C), 116.1, 122.9, 124.3 (d,
J
(P-C) = 4.1 Hz), 127.4, 128.0, 128.1, 128.2, 128.30, 128.31,
128.34, 128.4, 128.5, 128.8, 129.3, 130.9, 131.02, 131.06,
131.09, 131.11, 131.14, 131.18, 131.22, 131.43, 131.44, 131.45,
131.5, 131.6, 131.7, 132.6, 133.7, 133.8, 133.9, 134.2, 134.3,
134.6, 134.8, 134.9, 135.6, 150.6, 158.1 (the spectrum was
complicated). 31P NMR: δ 24.7 and 59.2. LC-MS: m/z 654
[M + 1]+. Anal. Calcd. for C40H33NO2P2S: C, 73.49; H, 5.09;
N, 2.14. Found: C, 73.38; H, 5.15; N, 2.19.
Compound (Z)-3i (lower Rf). Yield: 0.208 g (62%, E + Z);
0.151 g (Z, isolated, 45%). Mp: 232–236°C. IR (KBr): 3187,
1
3058, 1628, 1474, 1248, 1059, 791 cmꢀ1. H NMR (500 MHz):
δ 0.84 (s, 3H, CH3), 1.17 (s, 3H, CH3), 2.75–2.81 (m, 2H,
CHCH2), 3.12–3.16 (m, 1H, NH), 3.53–3.56 (m, 1H,
OCHAHB), 3.82–4.06 (m, 3H, OCHAHB + OCH2), 4.69–4.76
(m, 1H, CHNH), 7.01 (d, 3J(H-H) = 9.0 Hz, 1H, Ar-H), 7.19–
7.22 (m, 3H, Ar-H), 7.35–7.52 (m, 9H, Ar H), 7.74–7.78 (m,
2H, Ar H), 7.84–7.88 (m, 2H, Ar H). 13C NMR (125 MHz): δ
21.2, 21.9, 32.4 (d, J(P-C) = 6.3 Hz, C(CH3)2), 33.1 (dd, J
(P-C) ~ 10.4 Hz, J(P-C) ~ 3.8 Hz,CH2), 44.8 (s, NHCH), 76.0 (d,
J(P-C) = 6.4 Hz, OCH2(A)), 76.1 (d, J(P-C) = .6.0 Hz, OCH2
(B)), 108.7 (d, 1J(P-C) = 174.6 Hz, PC = C), 118.4, 126.0 (d, J
(P-C) = 5.4 Hz), 128.3, 128.6 (d, J(P-C) = 6.1 Hz), 128.7 (d, J
(P-C) = 5.6 Hz), 129.0, 129.7, 131.5 (d, J(P-C) = 11.1 Hz), 131.6
(d, J(P-C) = 11.4 Hz), 132.0 (d, J(P-C) = 3.5 Hz), 132.1 (d, J
(P-C) = 2.9 Hz), 132.2 (d, J(P-C) = 6.3 Hz), 133.5, 133.9, 134.1
(d, J(P-C) = 2.0 Hz), 134.3, 134.7, 150.0, 159.9. 31P NMR: δ 9.8
and 59.5. LC-MS: m/z 670 [M]+, 672 [M + 2]+ and 674
[M + 4]+. Anal. Calcd. for C33H31Cl2NO4P2S: C, 59.11; H,
4.66; N, 2.09. Found: C, 59.25; H, 4.56; N, 2.15.
Compound (Z)-6b (higher Rf). Yield: 0.107 g (31%; using
0.5 mmol of allene 5). Mp: 190–194°C. IR (KBr): 3113, 3058,
1630, 1474, 1265, 1165, 926 cmꢀ1 1H NMR: (500 MHz): δ
.
2.65–2.70 (m, 1H, CHCHA), 2.87–2.91 (m, 1H, CHCHB), 3.66–
3.71 (m, 1H, NH), 4.66–4.73 (m, 1H, CHNH), 6.08 (d, 3J(H-
H) = 8.8 Hz, 1H, Ar-H), 7.16–7.48 (m, 19H, Ar-H), 7.64–7.86
(m, 8H, Ar-H). 13C NMR (125 MHz): δ 33.3 (dd → t, J(P-C) ~ J
1
(P-C) ~ 6.1 Hz, CH2), 44.5 (NHCH), 115.8 (d, J(P-C) = 95.1 Hz,
PC = C), 117.5, 125.75, 125.79, 127.5, 127.7, 128.0, 128.1,
128.26, 128.30, 128.38, 128.43, 128.5, 128.6, 129.2, 130.8,
130.9, 131.0, 131.1, 131.2, 131.4, 131.47, 131.51, 131.6, 131.8,
132.3, 133.4, 133.9, 134.0, 134.1, 134.4, 134.5, 134.9, 135.4,
149.2, 157.8 (the spectrum was complicated). 31P NMR: δ 24.7
and 59.3. LC-MS: m/z 688 [M]+and 690 [M + 2]+. Anal. Calcd.
for C40H32ClNO2P2S: C, 69.81; H, 4.69; N, 2.04. Found: C,
69.73; H, 4.61; N, 2.08.
Compound (E + Z)-3j.
0.5 mmol of allene 2e). Mp: 240–244°C. IR (KBr): 3198, 2963,
1628, 1472, 1258, 1057, 806 cmꢀ1 1H NMR (500 MHz): (E/
Yield: 0.27 g (78%, E + Z; using
.
Z = ~1:1). Major isomer: δ 0.67 (s, 3H, CH3), 0.76 (s, 3H, CH3),
2.23–2.60 (m, 2H, CHCH2), 3.06–4.06 (m, 5H, OCH2
(A) + OCH2(B) + NH), 4.59 (br m, 1H, CHNH), 7.03–7.95 (m,
19H, Ar-H), 8.24–8.26 (m, 1H, Ar-H). Minor isomer: δ 1.07 (s,
6H, 2 CH3); remaining peaks were merged with peaks due to
the major isomer. 13C NMR (125 MHz): δ 21.1, 21.2, 21.87,
Acknowledgments. We thank the Department of Science and
Technology (DST, New Delhi) for financial support and for
the single crystal X-ray diffractometer facility at the University of
Hyderabad, and UGC (New Delhi) for equipment under UPE and
CAS programs. K. C. K. thanks DST for a J. C. Bose fellowship.
R. R. S. and R. K. thank CSIR (New Delhi) for fellowships. TRNP
thanks UGC for a fellowship.
21.88, 32.4 (d, J(P-C)= 6.3Hz, C(CH3)2) and 32.5 (d,
J
Journal of Heterocyclic Chemistry
DOI 10.1002/jhet

May 2014
Phosphine Catalyzed Synthesis of Phosphono-chromans
767
[8] (a) Kumara Swamy, K. C.; Balaraman, E.; Satish Kumar, N.
Tetrahedron 2006; 62, 10152; (b) Chakravarty, M.; Kumara Swamy, K.
C. J. Org Chem 2006, 71, 9128; (c) Chakravarty, M.; Kumara Swamy,
K. C. Synthesis 2007, 3171; (d) Chakravarty, M.; Bhuvan Kumar, N.
N.; Sajna, K. V.; Kumara Swamy, K. C. Eur J Org Chem 2008, 4500;
(e) Balaraman, E.; Srinivas, V.; Kumara Swamy, K. C. Tetrahedron
2009, 65, 7603; (f) Phani Pavan, M.; Chakravarty, M.; Kumara Swamy,
K. C. Eur J Org Chem 2009, 5927; (g) Srinivas, V.; Balaraman, E.; Sajna,
K. V.; Kumara Swamy, K. C. Eur J Org Chem 2011, 4222; (h) Sajna, K.
V.; Kotikalapudi, R.; Chakravarty, M.; Bhuvan Kumar, N. N.; Kumara
Swamy, K. C. J. Org Chem 2011, 76, 920.
[9] (a) Crystallographic data for the structure (Z)-3a have been
deposited with the Cambridge Crystallographic Data Centre as supple-
mentary publication number CCDC 918124. Copies of the data can be
obtained free of charge, on application to CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK [fax: +44(1223)336033 or e-mail:
deposit@ccdc.cam.ac.uk]; (b) Sheldrick, G. M. SADABS, Siemens Area
Detector Absorption Correction; University of Göttingen: Germany, 1996;
(c) Sheldrick, G. M. SHELX-97: A Program for Crystal Structure Solution
and Refinement; University of Göttingen: Germany, 1997; (d) Sheldrick,
G. M. SHELXTL NT Crystal Structure Analysis Package, Version 5; Bruker
AXS Analytical X-ray System: WI (USA), 1999; (e) (Z)-3a: colorless block,
C33H32NO4P2S, M = 600.61, Monoclinic, Space group P2(1)/c, a = 13.459
(3), b = 15.365(3), c = 16.616(3) Å, β = 112.72(2)o, V = 3169.5(11) Å,3
Z = 4, μ = 0.240 mm-1, data/restrains/parameters: 4578/0/372, R indices
(I > 2σ(I)): R1 = 0.0832, wR2 (all data) = 0.1983.
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Journal of Heterocyclic Chemistry
DOI 10.1002/jhet