Synthesis of the four enantiomers of diethyl 1,2-di(N-Boc-amino)propylphosphonates

Article abstract of DOI:10.1016/j.tetasy.2017.09.003

A simple and efficient synthetic strategy to all four enantiomerically pure diethyl 1,2-di(N-Boc-amino)propylphosphonates has been elaborated starting from the corresponding N-[(R)-(1-phenylethyl)]aziridine-(2S)- and N-[(S)-(1-phenylethyl)]aziridine-(2R)-

Full text of DOI:10.1016/j.tetasy.2017.09.003

Tetrahedron: Asymmetry xxx (2017) xxx–xxx
Contents lists available at ScienceDirect
Tetrahedron: Asymmetry
journal homepage: www.elsevier.com/locate/tetasy
Synthesis of the four enantiomers of diethyl 1,2-di(N-Boc-amino)
propylphosphonates
⇑
⇑
Iwona E. Głowacka , Dorota G. Piotrowska , Andrzej E. Wróblewski, Aleksandra Trocha
Bioorganic Chemistry Laboratory, Faculty of Pharmacy, Medical University of Łód ´z , 90-151 Łód ´z , Muszy n´ skiego 1, Poland
a r t i c l e i n f o
a b s t r a c t
Article history:
A simple and efficient synthetic strategy to all four enantiomerically pure diethyl 1,2-di(N-Boc-amino)
propylphosphonates has been elaborated starting from the corresponding N-[(R)-(1-phenylethyl)]aziri-
dine-(2S)- and N-[(S)-(1-phenylethyl)]aziridine-(2R)-carboxaldehydes, employing a one-pot three-com-
ponents Kabachnik-Fields reaction followed by the hydrogenolytic removal of the chiral auxiliary and
aziridine ring opening with simultaneous protection of the amino groups as the N-Boc derivatives.
Ó 2017 Elsevier Ltd. All rights reserved.
Received 25 July 2017
Revised 21 August 2017
Accepted 8 September 2017
Available online xxxx
7
8,19
20
1
. Introduction
,3-Diaminobutanoic acid 1 belongs to a large group of non-
[(2S,3S)-
L
-erythro] was detected in antrimycin lavendomycin
9
and cirratiomycin while feldamycin contains the (2S,3R) isomer.
The 2-amino-3-(N-methylamino)butanoic acid fragment of
2
2
1
proteinogenic amino acids (Fig. 1). This compound has been found
to be a structural constituent of several polypeptide antibiotics, e.g.
pacidomycins has a (2S,3S)-configuration. It is noteworthy that
epimerization at C2 of naturally occurring isomers of 1 was
observed under drastic conditions of acidic hydrolysis (6 M HCl)
of polypeptides leaving some doubt as to the reliability of the early
findings.
1
2
3
4
aspartocin,
glumamycin,
laspartomycin,
tsushimycin,
amphomycin, feldamycin,6 antrimycin,7 lavendomycin,8 and cir-
5
9
ratiomycins, and it was also identified in hydrolysates obtained
from root nodule of Lotus tenuis after inoculation with the Rhizo-
bium strain NZP2213.10 Recently, its 3-(N-methyl) derivative was
discovered as an important structural subunit in uridyl peptide
For the synthesis of 1, several pathways have been elaborated
beginning with the ammonolysis of 2,3-dibromobutanoic acid
1,22
or the bromine for amino exchange with azides followed by triph-
1
1,12
23
antibiotics pacidomycins, mureidomycins and napsamycins.
enylphosphine and hydrolysis of iminophosphoranes. Early syn-
theses of the enantiomers of 2,3-diaminobutanoic acid employed
threonine and allothreonine isomers as starting materials.2
Several elegant diastereoselective syntheses of the enantiomers
4–28
NH
2
NH
2
NH2
NH2
COOH
2
COOH
2
COOH
COOH
Me
Me
Me
Me
of 1 have been elaborated so far and they include the palladium
NH
NH
NH2
NH2
29
(
II)-catalyzed rearrangement of allylic trichloroacetimidates,
(
2S,3R)-1
(1S,2S)-1
(1R,2R)-1
(1R,2S)-1
addition of methylmagnesium bromide to serine-derived
3
0
nitrones, Sharpless aminohydroxylation of crotonate followed
Figure 1. 2,3-Diaminobutanoic acid 1.
31
by the HOC2 to H
bisacylamino)crotonate in the presence of chiral catalysts,
opening the respective aziridines with trimethylsilyl azide,
2
NC2 transformations, hydrogenation of E-
32,33
(
34
These achievements have generated interest in the synthesis
and stereochemistry of 2,3-diaminobutanoic acid since, for exam-
ple, it has been firmly established that amphomycin (glumamycin)
3
5
employing arylthionitrooxiranes chemistry or a conjugate addi-
tion of homochiral lithium N-benzyl-N- -methylbenzyl amide to
a
3
6
trans-crotonate and electrophilic amination with trisyl azide
contains two different diastereoisomers [(2R,3R)-
D
-erythro and
and the same
and finally allyl cyanate to isocyanate rearrangement.37
-threo] of 2,3-diaminobutanoic acid5
,13,14
(
2S,3R)-L
1
5,16
Over the last several decades, interest in 1-aminophosphonates
as analogues of amino acids has led to important achievements in
synthetic chemistry and many interesting observations of their
biological activities as antibiotics, fungicides and herbicides.38
As close structural analogues of natural amino acids, they may
act alone or as phosphonopeptides as inhibitors of various
stereoisomers were found in structurally related aspartocins,
tsushimycins, and friulimicins. On the other hand, diastereoisomer
17
18
⇑
Corresponding authors. Tel.: 48 42 677 92 37; fax: +48 42 678 83 98.
E-mail addresses: iwona.glowacka@umed.lodz.pl (I.E. Głowacka),
dorota.piotrowska@umed.lodz.pl (D.G. Piotrowska).
http://dx.doi.org/10.1016/j.tetasy.2017.09.003
0
957-4166/Ó 2017 Elsevier Ltd. All rights reserved.
Please cite this article in press as: Głowacka, I. E.; et al. Tetrahedron: Asymmetry (2017), http://dx.doi.org/10.1016/j.tetasy.2017.09.003

2
I. E. Głowacka et al. / Tetrahedron: Asymmetry xxx (2017) xxx–xxx
enzymes of interest in drug development. In the search for new
potentially active compounds as well as in order to modify the
known activity of 1-aminoalkanephosphonates, additional phar-
macophoric groups have been installed in the alkyl chain, first of
all amino and hydroxy groups.
13, diastereoisomeric aminophosphonates 6 and 11 were subjected
to catalytic hydrogenation.
2
. Results and discussion
The enantiomerically pure aldehydes (2S,1 S)- and (2R,1 S)-5 as
The inhibition of various aminopeptidases by substituted
0
0
3
9
0
0
6
1
diaminoalkanephosphonates was discovered many years ago
well as (2S,1 R)- and (2R,1 R)-10 were obtained in good yields
and is still an active area of research.40 Furthermore, it was shown
that human fibroblast collagenase could be inhibited by pep-
tidomimetics with 1,2-diaminoethane- and 1,3-diamino-
propanephosphonate moieties. Replacement of the phosphate
fragment in phosphoramidone with substituted 1,3-diamino-
propanephosphonate residues provided analogues active against
endothelin converting enzyme.42 Phosphonotripeptides containing
0
0
(
70–77%), respectively from aziridines (2S,1 S)- and (2R,1 S)-3 and
0
0
(
2S,1 R)- and (2R,1 R)-8 in two steps which included a reduction
6
2
63
of the ester group and a subsequent Swern oxidation of the
41
resulting alcohols 4 and 9 (Schemes 2 and 4). In the first step the
0
aldehyde (2R,1 S)-5 was subjected to the Kabachnik-Fields reaction
6
4,65
with triethyl phosphite and benzylamine in trifluoroethanol
to
0
afford the 1-benzylaminophosphonates (1S,2R,1 S)-6a and
1R,2R,1 S)-6b in a 1:4 ratio in 98% yield (Scheme 2) which were
separated on a silica gel column to give (1S,2R,1 S)-6a and
1
-amino-3-guaninyl- or 1,3-diaminopropanephosphonate compo-
0
(
4
3
nents appeared active against trypsin-like serine proteases or
glutathionylspermidine synthetase,44 respectively. In the search
for new integrin antagonists, it has recently been discovered that
N-substituted 1,2-diaminoethanephosphonates are very effective
as bioisosters of the carboxylic MIDAS binding motif.45
0
0
(
1R,2R,1 S)-6b in 13% and 56% yield, respectively.
0
On the other hand, when aldehyde (2S,1 S)-5 was subjected to
phosphorylation under the same conditions (Scheme 3), a 2:3 mix-
0
0
ture of the 1-amninophosphonates (1S,2S,1 S)-7a and (1R,2S,1 S)-
b was produced almost quantitatively. Unfortunately, several
For this reason, the synthetic availability of enantiomerically
pure aminophosphonates is of great importance and their stereos-
elective syntheses have recently been reviewed.46,47 In the major-
ity of cases, the hydrophosphorylation of imines (Kabachnik-Fields
7
attempts at separating them on a silica gel column failed.
Under these circumstances, in order to synthesise and effi-
ciently separate phosphonates with (1R,2S) and (1S,2S) configura-
reaction) was applied in
versions.
a
chiral pool or chiral catalyst
0
tions the aldehyde (2S,1 R)-10 was employed. The phosphonates
4
8,49
1
1a (ent-6a) and 11b (ent-6b) were obtained as described above
Several approaches have been developed for the synthesis
,2-aminoalkanephosphonates. Among them, the opening of an
in 12% and 55% yield, respectively (Scheme 4).
The respective enantiomers of diethyl 1,2-di(N-Boc-amino)
propylphosphonates 13 were obtained by catalytic hydrogenation
performed in the presence of Boc O to execute the aziridine ring
2
cleavage, removal of the N-(1-phenylethyl) and N-benzyl groups
and the protection of the amino groups (Scheme 5).
1
aziridine ring with nitrogen nucleophiles (ammonia, alkylamines)
has been the most common.40,50–52 However, other methods have
been explored and they include the Arbuzov reaction on
4
-acetoxy-3-phthalimidoazetidin-2-one to obtain enantiomeri-
53
cally pure (2R,3R)-diamino-3-phosphonopropanoic acid; alkyla-
tion of homochiral imidazolidinones, which contained
phosphorylated glycine moiety to prepare a series of enantiomeri-
It should be noted that the phosphonate (1R,2S)-13 obtained by
our methodology was identical in all respects with the one previ-
a
5
9
ously described.
The absolute stereochemistry of (1R,2S)-13 has already been
5
4
cally pure
a
-branched 1,2-diaminoethanephosphonates;
and
55
5
9
opening of enantiomeric sulfamidates. Furthermore, enantioen-
riched 2-aryl-1,2-diaminoethylphosphonates were synthesized
proved. In our preparation of this phosphonate, the (S)-configu-
ration at C2 follows the stereochemistry of its precursors: the
6
1
0
from phosphonoglycine benzophenone imines and
a-amidosul-
known
(
aldehyde (2S,1 R)-10 and the starting phosphonate
fones under basic conditions in the presence of homochiral
0
1R,2S,1 R)-11a. Since the (R)-configuration at C1 in the phospho-
5
6
catalysts,
while racemic 1,2-diaminoethylphosphonates were
nate (1R,2S)-13 prepared by our method has already been estab-
5
9
obtained from anions of (isocyanato)methylphosphonates and
N-acylimines or their synthetic analogues followed by
desulfurization and hydrolysis.57 Various modifications of the
Kabachnik-Fields reaction such as additions to chiral N-sulfonyl
lished, the minor phosphonate 11a obtained from the aldehyde
0
0
(
2S,1 R)-10 is the (1R,2S,1 R)-diastereoisomer, while the major pro-
0
duct (1S,2S,1 R)-11b has the opposite configuration at C1
(Scheme 4). The same line of reasoning allowed us to conclude that
5
8
59,60
45
imines, chiral nitrones
and to imines complete the scope
the minor and major phosphonates 6a and 6b obtained from the
of synthetic methods of 1,2-diaminoalkanephosphonates.
Herein we describe the asymmetric synthesis of all four enan-
tiomerically pure protected diethyl 1,2-diaminopropanephospho-
0
0
0
aldehyde (2R,1 S)-5 have the (1S,2R,1 S) and (1R,2R,1 S)-stereo-
0
chemistry, respectively (Scheme 2) since (1S,2R,1 S)-6a was later
transformed into the phosphonate (1S,2R)-13 (Scheme 5), the
5
9
nates
2 (Fig. 2) by employing the configurationally stable
enantiomer of the known compound (1R,2S)-13.
0
0
61
aziridine aldehydes (2S,1 S)- and (2R,1 S)-5 as convenient starting
materials (Scheme 1).
We noticed that HC1 in the major aminophosphonate
0
(
1R,2R,1 S)-6b (d = 2.46 ppm) resonates at greatly higher field in
Our synthetic strategy is outlined on Scheme 1 and takes advan-
tage of the Kabachnik-Fields reaction to form a CAP bond in
diastereoisomeric aminophosphonates 6/7 and 11/12 while open-
ing of the aziridine ring would allow for future functionalisation.
To synthesise diethyl 1,2-di(N-Boc-amino)propylphosphonates
comparison with that of the minor aminophosphonate
0
(
1S,2R,1 S)-6a (d = 3.04 ppm). This observation further supports
the configurational assignments for 6a and 6b, since it has been
earlier detected for diastereoisomeric pairs of the addition prod-
ucts to the enantiomeric aziridine aldehydes 5 for carbon61 as well
NH
2
NH
2
NH
2
NH
2
P(O)(OEt)
NH2
1R,2R)-2
2
P(O)(OEt)
NH2
(1R,2S)-2
Figure 2. Structures of enantiomers of 1,2-diaminopropanephosphonate 2.
2
P(O)(OEt)
NH2
(1S,2R)-2
2
P(O)(OEt)
NH2
(1S,2S)-2
2
Me
Me
Me
Me
(
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I. E. Głowacka et al. / Tetrahedron: Asymmetry xxx (2017) xxx–xxx
3
Ph
Ph
1
'
1'
H
H
H
H
N
P(O)(OEt)
2
N
Me
Me
CHO
NHBn
1S,2R,1'S)-6a
1R,2R,1'S)-6b
(2R,1'S)-5
(
(
Ph
Ph
1'
1
'
H
H
H
H
N
P(O)(OEt)2
N
Me
Me
CHO
NHBn
(
(
1S,2S,1'S)-7a
1R,2S,1'S)-7b
(2S,1'S)-5
NHBoc
P(O)(OEt)
2
Me
NHBoc
Ph
Ph
1'
1
'
Me
H
Me
H
13
N
P(O)(OEt)
2
N
H
H
CHO
NHBn
1R,2S,1'R)-11a
1S,2S,1'R)-11b
(
(2S,1'R)-10
(
Ph
Ph
1
'
1'
Me
H
Me
H
N
P(O)(OEt)
2
N
H
H
CHO
NHBn
1R,2R,1'R)-12a
1S,2R,1'R)-12b
(
(2R,1'R)-10
(
Scheme 1. Retrosynthesis of diethyl 1,2-di(N-Boc-amino)propylphosphonates.
Ph
1'
Ph
Ph
H
H
R
H
H
H
H
c.
N
N
P(O)(OEt)
+
N
P(O)(OEt)2
Me
Me
2
Me
NHBn
NHBn
(
2R,1'S)-3 R = COOMe
6a
6b
a.
b.
(
2R,1'S)-4 R = CH
OH
2
(2R,1'S)-5 R = CHO
Scheme 2. Reagents and conditions: (a) NaBH
4 h.
4
–LiCl, 0 °C to rt, 16 h, 94%; (b) DMSO, (COCl)
2
, ꢀ78 °C, 1 h, TEA, ꢀ78 °C to rt, 15 min, 70%; (c) (EtO)
3
2
P, BnNH , CF
3
CH
2
OH, rt,
2
Ph
1
Ph
Ph
'
H
H
H
H
H
H
a.
N
N
P(O)(OEt)2
+
N
P(O)(OEt)2
Me
Me
Me
CHO
NHBn
NHBn
(
2S,1'S)-5
7a
7b
2 3 2
P, BnNH , CF CH OH, rt, 24 h.
Scheme 3. Reagents and conditions: (a) (EtO)
3
as phosphorus nucleophiles.66 Furthermore, this shielding effect by
Ph–CH
(Fig. 3, blue arrows).
2 2
group (d = 7.00 ppm) and CH APh (d = 3.50 and 3.61 ppm)
⁄
the PhAC is extended on the H
in (1R,2R,1 S)-6b vs. 3.88 and 3.91 ppm in (1S,2R,1 S)-6a] and to
2
CAPh protons [3.50 and 3.61 ppm
0
0
In addition, the appearance of NOESY correlations between
⁄
some extent on the ortho-protons of the PhACH
2
group
HC Ph (d = 2.56 ppm) and both H
S
AC3 (d = 1.45 ppm) and HC2
0
0
[
7.00 ppm in (1R,2R,1 S)-6b vs. 7.3–7.4 ppm in (1S,2R,1 S)-6a].
(d = 1.87 ppm) as well as between HCP (d = 3.04 ppm) and both
AC3 (d = 2.09 ppm) and H CPh (d = 3.88 and 3.91 ppm) together
with a large upfield shift ( d = 0.64 ppm) of H AC3 when com-
AC3 as a result of the aromatic ring current exerted
These conclusions are strongly supported by the appearance of
H
R
2
the NOESY correlations in 6b between the ortho protons of the
D
S
⁄
⁄
⁄
PhAC (d = 7.36 ppm) and both HAC (d = 2.45 ppm) and MeAC
d = 1.47 ppm) as well as between the ortho-protons of the
pared with H
R
⁄
(
by PhC allow for unequivocal assignments of chemical shifts of
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4
I. E. Głowacka et al. / Tetrahedron: Asymmetry xxx (2017) xxx–xxx
Ph
Ph
Ph
Me
1'
H
R
Me
H
Me
H
c.
N
N
P(O)(OEt)2
+
N
P(O)(OEt)2
H
H
H
NHBn
11a (ent-6a)
NHBn
11b (ent-6b)
(
2S,1'R)-8 R = COOMe
a.
b.
(
2S,1'R)-9 R = CH
OH
2
(
2S,1'R)-10 R = CHO
Scheme 4. Reagents and conditions: (a) NaBH
4
–LiCl, 0 °C to rt, 16 h, 79%; (b) DMSO, (COCl)
2
, ꢀ78 °C, 1 h, TEA, ꢀ78 °C to rt, 15 min,77%; (c) (EtO)
3 2 3 2
P, BnNH , CF CH OH, rt, 24 h.
Ph
C3 resonances in the 1H NMR spec-
identification of prochiral H
2
1
'
NHBoc
0
H
H
trum of (1R,2R,1 S)-6b was accomplished (Figure 3, green arrows).
a
N
P(O)(OEt)2
P(O)(OEt)2
Me
3
3
Me
3
Based on the values of J(H1AH2) = 2.9 Hz and J(PCCCH )
=
0 Hz, which are only attainable for the gauche orientations of
the coupled nuclei, we suggest that the phosphonate (1S,2R)-13
in chloroform-d adopts the conformation shown in Figure 4.
NHBn
NHBoc
(
(
1S,2R,1'S)-6a
1R,2R,1'S)-6b
(1S,2R)-13
(1R,2R)-13
Intramolecular hydrogen bonding between PCNC@Oꢁ ꢁ ꢁHANCCH
3
may stabilise this conformation and help overcome the steric
2
repulsions of the (EtO )P(O) and methyl groups.
Ph
1
'
NHBoc
3. Conclusions
Me
H
a
N
P(O)(OEt)
2
P(O)(OEt)
2
H
Me
0
0
The reactions of the aziridine aldehydes (2R,1 S)-5 and (2S,1 R)-
0 with triethyl phosphite and benzylamine in trifluoroethanol
NHBn
NHBoc
1
provided separable mixtures of the 1-benzylaminophosphonates
(
1R,2S,1'R)-11a
(1R,2S)-13
(1S,2S)-13
0
0
0
(
1S,2R,1 S)-6a and (1R,2R,1 S)-6b as well as (1R,2S,1 R)-11a and
(1S,2S,1'R)-11b
0
(
1S,2S,1 R)11b, respectively. Hydrogenolysis of 2,3-aziridine-1-
Scheme 5. Reagents and conditions: (a) H
2
2
, 20% Pd(OH) AC, Boc
2
O, ethanol, 2 d.
benzylaminophosphonates 6a and 6b as well as 11a and 11b in
the presence of Boc O gave the corresponding enantiomers of
,2-di(N-Boc-amino)propylphosphonates 13.
2
1
4
. Experimental
H
S
H
H S
4.1. General
H
H
H
H
H
N
P(O)(OEt)
NH
2
N
P(O)(OEt)2
1H NMR spectra were taken in CDCl
or DMSO-d on a Bruker
3 6
Avance III (600 MHz) with TMS as an internal standard; chemical
shifts d are given in ppm with respect to TMS and coupling con-
Me
Me
H
R
HR
H
H NH
H
H
H
1
3
31
H
H
stants J in Hz. C NMR and P NMR spectra were recorded for
CDCl or DMSO-d solutions on the Bruker Avance III (600 MHz)
H
3
6
spectrometer at 151 and 243 MHz, respectively. IR spectroscopic
data were measured on an Infinity MI-60FT-IR spectrometer. Melt-
ing points were determined on a Boetius apparatus and are uncor-
rected. Elemental analyses were performed by the Microanalytical
Laboratory of the Faculty of Pharmacy (Medical University of Lodz)
on a Perkin Elmer PE 2400 CHNS analyser. The following adsor-
bents were used: column chromatography, Merck silica gel 60
(70–230 mesh); analytical TLC, Merck TLC plastic sheets silica gel
(
1S,2R,1'S)-6a
(1R,2R,1'S)-6b
Figure 3. NOESY correlations in the aminophosphonates 6a and 6b.
EtO
O
EtO
P
6
0 F254. TLC plates were developed in ethyl acetate, ethyl acet-
H
H
CH
N
3
ate–methanol and dichloromethane–methanol solvent systems.
Visualization of spots was effected with iodine vapors. All solvents
were purified by methods described in the literature.
H
Boc
O
N
H
...
.
C
.
O
0
4
(
.2. Synthesis of aziridine phosphonates (1S,2R,1 S)-6a,
0
0
0
1R,2R,1 S)-6b and (1R,2S,1 R)-11a, (1S,2S,1 R)-11b (general
Figure 4. Preferred conformation of (1S,2R)-13.
procedure)
0
diastereotopic H
2
C3 in (1S,2R,1 S)-6a (Figure 3, green arrows). In a
A mixture of aziridine aldehyde 5 and 10 (1.00 mmol),
⁄
similar fashion based on NOESY correlations between HC
d = 2.45 ppm) and H
AC3 (d = 1.98 ppm) and HCP (d = 2.46 ppm) in addition to a sig-
nificant upfield shift ( d = 0.36 ppm) of H AC3 related to H AC3
benzylamine (1.20 mmol) and triethyl phosphite (0.95 mmol) in
trifluoroethanol (1 mL) was stirred at room temperature for 24 h.
The reaction mixtures were then concentrated in vacuo. The crude
product was chromatographed on a silica gel column with ethyl
(
S
AC3 (d = 1.62 ppm) as well as between
H
R
D
S
R
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I. E. Głowacka et al. / Tetrahedron: Asymmetry xxx (2017) xxx–xxx
5
0
acetate to give the respective pure phosphonates (1S,2R,1 S)-6a
4.3. Hydrogenolysis of aziridine-2-phosphonates (general
procedure)
0
0
0
and (1R,2R,1 S)-6b or (1R,2S,1 R)-11a and (1S,2S,1 R)-11b,
respectively.
0
A
solution of
aziridine-2-phosphonate
(1S,2R,1 S)-6a,
0
0
0
4
.2.1. Diethyl (S)-benzylamino{(R)-1-[(S)-1-phenylethyl]aziridi-
(1R,2R,1 S)-6b, (1R,2S,1 R)-11a or (1S,2S,1 R)-11b (1.00 mmol) in
0
n-2-yl}methylphosphonate (1S,2R,1 S)-6a
ethanol (5 mL) containing Boc
atmospheric pressure of hydrogen over 20% Pd(OH)
2
O (2.2 mmol) was stirred under an
AC (50 mg)
0
From aldehyde (2R,1 S)-5 (3.601 g, 20.5 mmol), phosphonate
2
0
(
1S,2R,1 S)-6a (1.009 g, 13%) was obtained as a slightly yellow oil.
at room temperature for 2 days. The suspension was filtered
through a layer of Celite, the solution was concentrated and chro-
matographed on a silica gel column with dichloromethane–metha-
nol (100:1, v/v). The appropriate fractions were collected and
crystallized from hexane to give the corresponding enantiomeri-
cally pure diethyl 1,2-di(N-Boc-amino)propylphosphonate 13.
IR (film):
m
a
= 3462, 3061, 2979, 2928, 1452, 1238, 1027, 754,
ꢀ1
20
D
1
7
01 cm . ½
ꢂ
= +34.8 (c 1.16, CHCl
3
). H NMR (600 MHz, CDCl
CH OP), 3.91
Ph), 3.88 (AB, J = 13.5 Hz, 1H, H CH Ph),
.04 (dd, J = 9.8 Hz, J = 4.0 Hz, 1H, HCP), 2.56 (q, J = 6.5 Hz, 1H,
), 2.09 (d, J = 3.5 Hz, 1H, H CH CCP), 1.87 (dtd, J = 6.5 Hz,
J = 4.0 Hz, J = 3.5 Hz, 1H, HCCP), 1.45 (d, J = 6.5 Hz, 1H, H CH CCP),
), 1.30 (t, J = 7.0 Hz, 3H, CH CH OP),
CH ):
OP). 13C NMR (151 MHz, CDCl
),
2.2 (d, J = 7.2 Hz, CCOP), 62.1 (d, J = 7.2 Hz, CCOP), 52.8 (d,
3
):
d = 7.33–7.23 (m, 10H), 4.12–4.04 (m, 4H, 2 ꢃ CH
3
2
(
AB, J = 13.5 Hz, 1H, H
a
CH
b
a
b
3
HCCH
3
a
b
a
b
4.3.1. Diethyl (1S,2R)-1,2-di(N-Boc-amino)propylphosphonate
1
1
.42 (d, J = 6.5 Hz, 3H, HCCH
.29 (t, J = 7.0 Hz, 3H, CH
3
3
2
(1S,2R)-13
0
3
2
3
From
aziridine-2-phosphonate
(1S,2R,1 S)-6a
(0.101 g,
d = 144.4, 139.9, 128.4, 128.3, 127.0, 126.9, 126.8, 69.8 (s, CCH
3
0.250 mmol), (1S,2R)-13 (0.052 g, 50%) was obtained as a white
6
solid (rhombus). Mp = 74–76 °C. IR (KBr):
m
= 3426, 3282, 2977,
ꢀ1
20
D
1
J = 161.2 Hz, CP), 52.6 (d, J = 6.3 Hz, CH
2
Ph), 37.0 (s, CCP), 29.9 (d,
1723, 1704, 1501, 1163 cm . ½
NMR (600 MHz, CDCl
(d, J = 8 Hz, 1H, HNCHCH
J = 2.9 Hz, 1H, HCP), 4.20–4.12 (m, 4H, 2 ꢃ CH
(m, 1H, CHCP), 1.47 (s, 9H, (CH C), 1.46 (s, 9H, (CH
J = 7.0 Hz, 3H, CH CH OP), 1.34 (t, J = 7.0 Hz, 3H, CH
(d, J = 7.0 Hz, 3H, CH
(d, J = 10.6 Hz, 1H, HNCHP), 6.60 (d, J = 7.7 Hz, 1H, HNCHCH
4.24 (ddd, J = 17.6 Hz, J = 10.6 Hz, J = 5.8 Hz, 1H, HCP), 4.04–3.96
CH OP), 3.79–3.75 (m, 1H, CHCP), 1.40 (s, 9H,
C), 1.37 (s, 9H, (CH
1.22 (t, J = 7.0 Hz, 3H, CH
aꢂ
= +25.9 (c 0.58, CHCl
3
).
H
J = 4.1 Hz, CCCP), 23.0 (s, CCH
3
), 16.6 (d, J = 5.0 Hz, CCOP), 16.5 (d,
J = 5.0 Hz, CCOP). P NMR (243 MHz, CDCl ): d = 25.36. Anal. Calcd
for C22 O: C, 64.16; H, 7.78: N, 6.80. Found: C,
3
): d = 5.22 (d, J = 10 Hz, 1H, HNCHP), 5.11
), 4.25 (ddd, J = 18.0 Hz, J = 10.3 Hz,
CH OP), 4.11–4.00
C), 1.36 (t,
CH OP), 1.29
CH). H NMR (600 MHz, DMSO-d ): d = 6.89
),
3
1
3
3
H
31
N
2
O
3
P ꢃ 0.5 H
2
3
2
6
4.11; H, 7.92; N, 6.83.
3
)
3
3 3
)
3
2
3
2
1
4
.2.2. Diethyl (R)-benzylamino{(R)-1-[(S)-1-phenylethyl]aziridi-
3
6
0
n-2-yl}methylphosphonate (1R,2R,1 S)-6b
3
0
From aldehyde (2R,1 S)-5 (3.601 g, 20.5 mmol), phosphonate
0
(
1R,2R,1 S)-6b (4.392 g, 56%) was obtained as a slightly yellow
(m, 4H, 2 ꢃ CH
3
2
oil. IR (film):
m
20
D
= 3456, 3061, 2980, 2929, 1453, 1234, 1026, 756,
(CH
3
)
3
3
)
3
C), 1.24 (t, J = 7.0 Hz, 3H, CH
3
CH
2
OP),
CH).
ꢀ
1
1
7
00 cm . ½
a
ꢂ
= +1.9 (c 0.90, CHCl
3
). H NMR (600 MHz, CDCl
3
):
3
CH OP), 1.07 (d, J = 6.7 Hz, 3H, CH
2
3
1
3
d = 7.36 (d, J = 7.7 Hz, 2H), 7.27–7.16 (m, 6H), 7.03 (d, J = 7.0 Hz,
H), 4.16–4.11 (m, 4H, 2 ꢃ CH CH OP), 3.61 (AB, J = 13.0 Hz, 1H,
CH Ph), 3.50 (AB, J = 13.0 Hz, H CH Ph), 2.46 (dd, J = 11.4
Hz, J = 8.8 Hz, 1H, HCP), 2.45 (q, J = 6.6 Hz, HCCH ), 1.98 (d,
J = 3.4 Hz, 1H, CH CCP), 1.80 (dddd, J = 8.8 Hz, J = 6.6 Hz,
J = 3.4 Hz, J = 2.9 Hz, 1H, HCCP), 1.62 (d, J = 6.6 Hz, H CH CCP),
), 1.32 (t, J = 7.0 Hz, 3H, CH CH OP),
CH ):
OP). 13C NMR (151 MHz, CDCl
C NMR (151 MHz, CDCl
C@O), 80.3, 79.5, 63.1 (d, J = 6.7 Hz, CCOP), 62.4 (d, J = 6.7 Hz,
CCOP), 50.5 (d, J = 152.9 Hz, CP), 48.0 (CCP), 28.4 (3 ꢃ CH ), 28.3
(3 ꢃ CH ), 17.8 (CCCP), 16.4 (d, J = 5.7 Hz, CCOP), 16.3 (d,
J = 5.7 Hz, CCOP). P NMR (243 MHz, DMSO-d
Anal. Calcd for C17 O: C, 47.11; H, 8.66; N,
P ꢃ 1.25 H
6.47. Found: C, 46.95; H, 8.43; N, 6.18.
3
): d = 155.4 (C@O), 155.3 (d, J = 6.7 Hz,
2
3
2
H
a
b
a
b
3
3
3
3
1
H
a
b
6
): d = 23.61, 23.16.
a
b
H
35
N
2
O
7
2
1
1
.47 (d, J = 6.6 Hz, 3H, HCCH
.31 (t, J = 7.0 Hz, 3H, CH
3
3
2
3
2
3
d = 143.9, 140.0, 128.6, 128.1, 128.0, 127.6, 127.2, 126.6, 70.3,
2.3 (d, J = 7.2 Hz, CCOP), 62.2 (d, J = 7.2 Hz, CCOP), 59.4 (d,
J = 158.9 Hz, CP), 52.5 (d, J = 6.3 Hz, CH Ph), 39.3 (d, J = 4.3 Hz,
CCP), 32.9 (s, CCCP), 22.2 (s, CCH
), 16.5 (d, J = 5.6 Hz, 2 ꢃ CCOP).
): d = 24.61. Anal. Calcd for C22
O: C, 64.16; H, 7.78: N, 6.80. Found: C, 64.16; H, 7.89;
4.3.2. Diethyl (1R,2S)-1,2-di(N-Boc-amino)propylphosphonate
6
(1R,2S)-13
0
2
From
aziridine-2-phosphonate
(1R,2S,1 R)-11a
(0.161 g,
3
0.400 mmol), (1R,2S)-13 (0.080 g, 49%) was obtained as white nee-
3
1
20
P NMR (243 MHz, CDCl
3
H
31
N
2
O
3
-
dles. Mp = 69–70 °C. [
P ꢃ 0.5 H
48.61; H, 8.64; N, 6.59.
a
2
]
D
= ꢀ24.9 (c 0.81, CHCl
3
). Anal. Calcd for
P ꢃ 0.5 H
2
C
17
H
35
N
2
O
7
O: C, 48.64; H, 8.58; N, 6.67. Found: C,
N, 6.92.
4
.2.3. Diethyl (S)- and (R)-benzylamino{(S)-1-[(S)-1-phenyleth-
4.3.3. Diethyl (1R,2R)-1,2-di(N-Boc-amino)propylphosphonate
0
yl]aziridin-2-yl}methylphosphonates (1S,2S,1 S)-7a and (1R,2S,
(1R,2R)-13
0
0
1
S)-7b
From
aziridine-2-phosphonate
(1R,2R,1 S)-6b
(0.109 g,
For crude mixture of diastereoisomers (2:3) 31P NMR (243 MHz,
0.271 mmol), (1R,2R)-13 (0.068 g, 61%) was obtained as a white
CDCl
3
): d = 25.60, 25.18.
solid (rhombus). Mp = 83–86 °C. IR (KBr):
m
= 3321, 2978, 1716,
ꢀ1
20
D
1
1
685, 1511, 1166 cm . ½
a
ꢂ
3
= +15.5 (c 0.92, CHCl ). H NMR
4
.2.4. Diethyl (R)-benzylamino{(S)-1-[(R)-1-phenylethyl]aziridi-
(600 MHz, CDCl
3
): d = 5.18 (d, J = 10.0 Hz, 1H, HNCHP), 4.95 (d,
), 4.20–4.14 (m, 4H, 2 ꢃ CH CH OP),
4.10–4.03 (m, 1H, CHCP), 4.00 (ddd, J = 17.1 Hz, J = 10.0 Hz,
J = 7.0 Hz, 1H, HCP), 1.47 (s, 9H, (CH C), 1.46 (s, 9H, (CH C),
1.36 (t, J = 7.1 Hz, 3H, CH CH OP), 1.35 (t, J = 7.1 Hz, 3H, CH CH
OP), 1.32 (d, J = 6.5 Hz, 3H, CH CH). H NMR (600 MHz, DMSO-
): d = 6.85 (d, J = 10.3 Hz, 1H, HNCHP), 6.69 (d, J = 8.9 Hz, 1H,
HNCHCH CH OP, HCP, CHCP), 1.37 (s,
9H, (CH C), 1.19 (t, J = 7.1 Hz, 3H, CH
OP), 1.18 (t, J = 7.1 Hz, 3H, CH CH OP), 1.00 (d, J = 6.4 Hz, 3H, CH
CH). C NMR (151 MHz, CDCl
0
n-2-yl}methylphosphonate (1R,2S,1 R)-11a
J = 7.7 Hz, 1H, HNCHCH
3
3
2
0
From aldehyde (2S,1 R)-10 (0.736 g, 4.2 mmol), phosphonate
0
(
1R,2S,1 R)-11a (0.196 g, 12%) was obtained as a slightly yellow
3
)
3
3 3
)
2
D
0
oil. ½
a
ꢂ
= ꢀ36.8 (c 1.35, CHCl
3
). Anal. Calcd for C22
H
31
N
2
O
3
P ꢃ 0.5
3
2
3
2
-
1
H
2
O: C, 64.16; H, 7.78: N, 6.80. Found: C, 64.42; H, 7.85; N, 6.88.
3
d
6
4
.2.5. Diethyl (S)-benzylamino{(S)-1-[(R)-1-phenylethyl]aziridi-
3
), 4.00–3.86 (m, 6H, 2 ꢃ CH
3
2
0
n-2-yl}methylphosphonate (1S,2S,1 R)-11b
3
)
3
C), 1.35 (s, 9H, (CH
3
)
3
3
CH
2
-
-
0
From aldehyde (2S,1 R)-10 (0.736 g, 4.2 mmol), phosphonate
3
2
3
0
13
(
1S,2S,1 R)-11b (0.925 g, 55%) was obtained as a slightly yellow
3
): d = 155.7 (d, J = 6.8 Hz, C@O),
2
D
0
oil. ½
a
ꢂ
= ꢀ2.9 (c 1.13, CHCl
3
). Anal. Calcd for C22
H
31
N
2
O
3
P ꢃ H
2
O:
155.6 (C@O), 80.1, 79.4, 62.7 (d, J = 6.8 Hz, CCOP), 62.6 (d,
J = 6.8 Hz, CCOP), 52.2 (d, J = 151.6 Hz, CP), 47.0 (CCP), 28.4
C, 62.78; H, 7.84: N, 6.65. Found: C, 62.45; H, 7.72; N, 6.82.
Please cite this article in press as: Głowacka, I. E.; et al. Tetrahedron: Asymmetry (2017), http://dx.doi.org/10.1016/j.tetasy.2017.09.003

6
I. E. Głowacka et al. / Tetrahedron: Asymmetry xxx (2017) xxx–xxx
(
1
2
3 ꢃ CH
3
), 28.3 (3 ꢃ CH
6.3 (d, J = 5.9 Hz, CCOP). P NMR (243 MHz, CDCl
2.19. Anal. Calcd for C17 P: C, 49.75; H, 8.60; N, 6.83.
3
), 18.7 (CCCP), 16.5 (d, J = 5.9 Hz, CCOP),
24. Atherton, E.; Meienhofer, J. Hoppe-Seyler’s Zeitschrift Physiol. Chem. 1973, 354,
31
689–696.
3
): d = 22.81,
2
2
5. Atherton, E.; Meienhofer, J. J. Antibiot. 1972, 25, 539–540.
6. Nakamura, Y.; Hirai, M.; Tamotsu, K.; Yonezawa, Y.; Shin, C. Bull. Chem. Soc. Jpn.
1995, 68, 1369–1377.
35 2 7
H N O
Found: C, 49.70; H, 8.55; N, 6.94.
2
2
7. Mangold, R.; Lieberknecht, A. J. Chem. Soc., Chem. Commun. 1990, 1216–1219.
8. Schmidt, U.; Mundinger, K.; Riedl, B.; Haas, G.; Lau, R. Synthesis 1992, 1201–
4
.3.4. Diethyl (1S,2S)-1,2-di(N-Boc-amino)propylphosphonate
1202.
(
1S,2S)-13
From
29. Gonda, J.; Helland, A. C.; Ernst, B.; Bellus, D. Synthesis 1993, 729–733.
30. Merino, P.; Lanaspa, A.; Merchan, F. L.; Tejero, T. Tetrahedron Lett. 1997, 38,
0
aziridine-2-phosphonate
(1S,2S,1 R)-11b
(0.300 g,
1
813–1816.
1. Han, H.; Yoon, J.; Janda, K. D. J. Org. Chem. 1998, 63, 2045–2048.
32. Kuwano, R.; Okuda, S.; Ito, Y. Tetrahedron: Asymmetry 1998, 9, 2773–2775.
0
.751 mmol), (1S,2S)-13 (0.185 g, 60%) was obtained as a white
3
2
0
solid. Mp = 86–88 °C. ½
a
ꢂ
= ꢀ16.1 (c 0.94, CHCl
3
). Anal. Calcd for
D
3
3. Robinson, A. J.; Stanislawski, P.; Mulholland, D.; He, L.; Li, H.-Y. J. Org. Chem.
001, 66, 4148–4152.
17 35 2 7
C H N O
P: C, 49.75; H, 8.60; N, 6.83. Found: C, 50.09; H, 8.90;
2
N, 6.98.
3
4. Lee, K.-D.; Suh, J.-M.; Park, J.-H.; Ha, H.-J.; Choi, H. G.; Park, C. S.; Chang, J. W.;
Lee, W. K.; Dong, Y.; Yun, H. Tetrahedron 2001, 57, 8267–8276.
5. Dumez, E.; Szeki, A. Synlett 2001, 1214–1216.
6. Bunnage, M. E.; Burke, A. J.; Davies, S. G.; Millican, N. L.; Nicholson, R. L.;
Roberts, P. M.; Smith, A. D. Org. Biomol. Chem. 2003, 1, 3708–3715.
3
3
Acknowledgments
Financial support from the Medical University of Łód z´ (503/3-
14-01/503-31-001 and 502-03/3-014-01/502-34-075) is grate-
37. Ichikawa, Y.; Egawa, H.; Ito, T.; Isobe, M.; Nakano, K.; Kotsuki, H. Org. Lett. 2006,
8, 5737–5740.
0
38. Aminophosphonic and Aminophosphinic Acids. Chemistry and Biological Activity;
Kukhar, V. P., Hudson, H. P., Eds.; Wiley: New York, 1999.
fully acknowledged.
39. Lejczak, B.; Kafarski, P.; Zygmunt, J. Biochemistry 1989, 28, 3549–3555.
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Please cite this article in press as: Głowacka, I. E.; et al. Tetrahedron: Asymmetry (2017), http://dx.doi.org/10.1016/j.tetasy.2017.09.003