Synthesis and catalytic activity of spaced ferrocene oxazolines

Article abstract of DOI:10.1135/cccc20031206

Chiral 2-[{N-aryl-N-(ferrocenylmethyl)amino}methyl]-4-(1-methylethyl)-4, 5-dihydroxazoles with various substituents at the aryl ring were prepared by alkylation of N-(ferrocenyl-methyl)anilines, FcCH₂NHC ₆H₄R (Fc = ferrocenyl), with (S)-2-(chloromethyl)-4-(1-methylethyl)-4,5-dihydrooxazole. The oxazoles, substituted anilines, and the precursors of the latter, the respective Schiff bases FcCH=NC₆H₄R, were characterized by standard methods and further studied by mass spectrometry. The oxazoles were further tested as chiral auxiliaries in the addition of diethylzinc to benzaldehyde but showed only negligible asymmetric induction (ee ca 10%), most likely due to steric hindrance of the nitrogen donor centres. This steric restriction seems to be lowered upon replacement of the substituted phenyl group with a benzyl substituent; compounds FcCH₂NHCH₂Ph and (R)-FcCH ₂NHCH(Me)Ph are easily alkylated yielding [FcCH₂NMe ₂(CH₂Ph)]I (9) and 2-[{N-(1-phenylethyl)-N-(ferrocenylmethyl)amino}methyl]-4-(1-methylethyl)-4, 5-dihydroxazole (10), respectively. Solid-state structures of FcCH ₂NHC₆H₄R (R = 2-Me and 4-Cl), 9, and 10 have been determined by single-crystal X-ray diffraction.

Full text of DOI:10.1135/cccc20031206

1206
Štěpnička et al.:
SYNTHESIS AND CATALYTIC ACTIVITY OF SPACED FERROCENE
OXAZOLINES
b
Petr ŠTĚPNIČKAa1,*, Tomáš BAŠEa2, Ivana CÍSAŘOVÁa3, Jiří KUBIŠTA ,
c1
c2
Štěpán VYSKOČIL and Martin ŠTÍCHA
a
Department of Inorganic Chemistry, Faculty of Science, Charles University, Hlavova 2030,
128 40 Prague 2, Czech Republic; e-mail: stepnic@natur.cuni.cz, tbase@centrum.cz,
cisarova@natur.cuni.cz
J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic,
Dolejškova 3, 182 23 Prague 8, Czech Republic; e-mail: kubista@jh-inst.cas.cz
Department of Organic Chemistry, Faculty of Science, Charles University, Hlavova 2030,
1
2
3
b
c
1
2
128 40 Prague 2, Czech Republic; e-mail: stepanv@natur.cuni.cz, sticha@natur.cuni.cz
Received April 14, 2003
Accepted May 12, 2003
Ch iral 2-[{N-aryl-N-(ferrocen ylm eth yl)am in o}m eth yl]-4-(1-m eth yleth yl)-4,5-dih ydroxazoles
with various substituen ts at th e aryl rin g were prepared by alkylation of N-(ferrocen yl-
m eth yl)an ilin es, FcCH2NHC6H4R (Fc = ferrocen yl), with (S)-2-(ch lorom eth yl)-4-(1-m eth yl-
eth yl)-4,5-dih ydrooxazole. Th e oxazoles, substituted an ilin es, an d th e precursors of th e
latter, th e respective Sch iff bases FcCH=NC6H4R, were ch aracterized by stan dard m eth ods
an d furth er studied by m ass spectrom etry. Th e oxazoles were furth er tested as ch iral auxilia-
ries in th e addition of dieth ylzin c to ben zaldeh yde but sh owed on ly n egligible asym m etric
in duction (ee ca 10%), m ost likely due to steric h in dran ce of th e n itrogen don or cen tres.
Th is steric restriction seem s to be lowered upon replacem en t of th e substituted ph en yl
group with a ben zyl substituen t; com poun ds FcCH2NHCH2Ph an d (R)-FcCH2NHCH(Me)Ph
are easily alkylated yieldin g [FcCH2NMe2(CH2Ph )]I (9) an d 2-[{N-(1-ph en yleth yl)-
N-(ferrocen ylm eth yl)am in o}m eth yl]-4-(1-m eth yleth yl)-4,5-dih ydroxazole (10), respectively.
Solid-state structures of FcCH2NHC6H4R (R = 2-Me an d 4-Cl), 9, an d 10 h ave been deter-
m in ed by sin gle-crystal X-ray diffraction .
Keyw ord s: Oxazolin es; Ferrocen es; Mass spectrom etry; Organ ozin c reagen ts; En an tio-
selective catalysis; Crystal structure; Ch iral ligan ds; Sch iff bases; Im in es; Am in es; X-ray dif-
fraction .
Ch iral 2-ferrocen yl-4,5-dih ydrooxazoles (h en ceforth referred to as corre-
spon din g oxazolin es) h avin g a fun ction al group on th e cyclopen tadien yl
rin g in a position adjacen t to th e oxazolin yl m oiety (type I) or on th e oth er
rin g (type II) h ave been used with success as ligan ds in a n um ber of cata-
lyzed en an tioselective reaction s1. More recen tly, th e class of ferrocen yl-
oxazolin e ligan ds h as been furth er exten ded to 4-ferrocen yloxazolin es2
Collect. Czech. Chem. Commun. (Vol. 68) (2003)
doi:10.1135/cccc20031206

Spaced Ferrocene Oxazolines
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(type III), wh ich also proved to be efficien t ligan ds for asym m etric cataly-
sis, wh ile som e n on -fun ction alized ferrocen yloxazolin es were used as elec-
troch em ical sen sors3.
In addition , substituted 2-ferrocen yloxazolin es I can be used as excellen t
startin g m aterials for th e preparation of plan ar-on ly ch iral ferrocen e com -
poun ds as th ey are readily accessible in stereom erically pure form via
diastereoselective orth o-lith iation /fun ction alization of C-ch iral oxazolin es
(I, Y = H), an d th e ch iral auxiliary, th e oxazolin e rin g, can be afterwards h y-
drolyzed an d subsequen tly m odified4,5
.
In th is con tribution , we describe th e syn th esis of variously substituted,
ch iral 2-[{N-aryl-N-(ferrocen ylm eth yl)am in o}m eth yl]-4-(1-m eth yleth yl)-
4,5-dih ydroxazoles an d of 2-[{N-(1-ph en yleth yl)-N-(ferrocen ylm eth yl)am i-
n o}m eth yl]-4-(1-m eth yleth yl)-4,5-dih ydroxazole, in wh ich th e addition al
don or (n itrogen ) atom an d th e oxazolin e rin g are separated by a m eth ylen e
group. Th e ligan ds possess a ch iral cen tre in position four of th e th e
oxazolin e n itrogen atom in h eren t in (S)-valin ol, th e ferrocen e un it actin g
on ly as an electron -don atin g, sterically well-defin ed stereodiscrim in atin g
substituen t. We also report catalytic activity of th e form er ligan ds in th e ad-
dition of dieth ylzin c on to ben zaldeh yde an d discuss th e obtain ed catalytic
results with regard to th e solid-state structures of several in term ediates an d
ligan ds, an d also som e m odel reaction s.
RESULTS AND DISCUSSION
2-[{N-Aryl-N-(ferrocenylmethyl)amino}methyl]-4-(1-methylethyl)-4,5-dihydroxazoles
Syn th esis an d Ch aracterization
Syn th esis of th e title com poun ds bearin g various substituen t at th e aryl an d
oxazolin e rin gs, 5 an d 6, is outlin ed in Sch em e 1. Th e startin g am in es 2
were prepared usin g an establish ed procedure: by reactin g ferrocen e-
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Štěpnička et al.:
carboxaldeh yde with rin g-substituted an ilin es to give th e respective Sch iff
6
bases 1 an d subsequen t reduction of aldim in es 1 with NaBH4 in m eth an ol.
(Ch lorom eth yl)oxazolin es 4 were obtain ed by con den sation of th e respec-
tive β-am in oalcoh ols with glycolic acid un der azeotropic water rem oval7
an d ch loration of th e resultin g (h ydroxym eth yl)oxazolin es 3 with
SCHEME 1
PPh 3/CCl4 m ixture8 (Sch em e 2). As th e last step, oxazolin es 5 an d 6 were
syn th esized by alkylation of N-(ferrocen ylm eth yl)an ilin es 2 with (ch loro-
m eth yl)oxazolin es 4 (Sch em e 1).
SCHEME 2
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Spaced Ferrocene Oxazolines
1209
Un fortun ately, th e m olecule-assem blin g alkylation step proved th e m ost
difficult in th e reaction sequen ce. Th e alkylation of th e sim plest am in e 2a
with n on -ch iral oxazolin e 4a to give 5a was in itially attem pted by reactin g
th e educts in aceton itrile, eth an ol or N,N-dim eth ylform am ide with or with -
out added base (Na2CO3, K2CO3) at room tem perature or by deproton ation
of 2a with LiBu followed by an addition of 4a. In n eith er case, h owever, th e
alkylated product was detected by th in -layer ch rom atograph y, MS an d
NMR spectra. Fin ally, th e alkylation reaction was effected by h eatin g a
2a–4a m ixture (1:2 m olar ratio) with out a solven t in th e presen ce of solid
K2CO3 (excess) for 36 h to 100 or 150 °C (tem perature in bath ) un der argon .
Oxazolin es 5 an d 6 were th en obtain ed usin g a sim ilar procedure: a m ixture
of am in e 2, oxazolin e 4 (2 equiv.) an d K2CO3 (3 equiv.) was h eated un der
argon to 80–90 °C for 48 h . Th e reaction produces com plex m ixtures from
wh ich th e oxazolin es were isolated by repeated colum n ch rom atograph y;
on ly com poun ds 5, an d 6a, 6c, 6d , 6f–6h could be isolated in pure form .
Th e reluctan ce of am in es 2 to un dergo th e N-alkylation can be ascribed to
steric factors, particularly to bulkiness of the substituents at the nitrogen atoms
an d possibly also to th e presen ce of th e con jugated electron -with drawin g
aryl group (see below).
All com poun ds were ch aracterized by spectral m eth ods (NMR, IR an d
m ass spectra) an d elem en tal an alysis (eith er stan dard or from h igh -
resolution m ass spectra). Th e Sch iff bases, wh ich were obtain ed as dark or-
an ge solids, exh ibited typical stron g ban d due to th e νC=N stretch in g at ca
1620 cm –1 in th eir IR an d sign als due to th e aldim in e m oiety at δH ca 8.3,
δC ca 160 in th e NMR spectra. Am in es 2 are yellow solids, sh owin g broad
νNH ban ds in IR spectra an d a broad reson an ce of th e NH proton at δH
3.5–3.9 in 1H NMR spectra. Th e in corporation of th e oxazolin e un it to form
oxazolin es 5 an d 6 is best in dicated by th e 13C NMR reson an ce of th e
pivotal carbon with in th e oxazolin e rin g at δC ca 164. Addition ally, th e
presen ce of a ch iral cen tre in 6 m akes all ferrocen e CH groups an d th e
m eth ylen e proton s, wh ich are observed as degen erate (en an tiotopic) sign als
in th e case of th e am in es an d Sch iff bases, n on -equivalen t (diastereotopic).
Mass Spectrom etry
All th e th ree series of com poun ds (Sch iff bases, am in es an d oxazolin es)
were studied by m ass spectrom etry. As sh own in Sch em e 3 (top) for 1a, m o-
lecular ion s of Sch iff bases (1• +) decom pose by eith er successive elim in ation
of cyclopen tadien yl radical (1a• + → m/z 224) an d th e iron atom (m/z 224 →
168), or by an elim in ation of Ph NC m olecule to give ferrocen e ion radical
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Štěpnička et al.:
(m/z 186), wh ich fragm en ts by a con secutive loss of its two cyclo-
pen tadien yl rin gs. Th e fragm en tation of th e am in es, dem on strated for 2a
in Sch em e 3 (bottom ) is differen t: th e m olecular ion 2a• + elim in ates ben -
zen e m olecule (2a• + → m/z 213) or an an ilin e radical Ph NH• to give
ferrocen ylm eth yl cation (or a product of its rearran gem en t; 2a• + → m/z 199).
Th e form er fragm en tation route con tin ues by a loss of HCN m olecule to
give ferrocen e ion radical wh ich fragm en ts as given above. Th us, th e two
path ways virtually m erge at th e fragm en t ion [FeC5H5]+ (m/z 121).
SCHEME 3
Th e prom in en t fragm en ation processes for Sch iff bases 1 (top) an d th e respective am in es 2
(bottom )
Oxazolin es 5 an d 6 (see Sch em e 4 for fragm en ation of 6a) fragm en t upon
electron im pact by a loss of th e un substituted cyclopen tadien yl rin g, a
cleavage of th e C–N bon d to produce ion s at m/z 199 due to [FcCH2]+ or an
isom eric species, or give rise to ion s isobaric with th e respective Sch iff base
by a form al elim in ation of th e correspon din g 2-m eth yloxazolin e from th e
m olecular ion s 6• +. Th e ion s isobaric with 1• +, wh ich dom in ate th e spectra
of oxazolin es 5 an d 6, furth er fragm en t as m en tion ed above for Sch iff bases
1 an d, h en ce, are m ost likely structurally sim ilar to th ose origin atin g from
ion ization of th e Sch iff bases.
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Spaced Ferrocene Oxazolines
1211
SCHEME 4
Fragm en tation sch em e of oxazolin es 5 an d 6 (sh own for 6a)
Catalysis
Sin ce its discovery9, en an tioselective addition of diorgan ylzin c reagen ts to
aldeh ydes h as becom e an establish ed tool for th e syn th esis of ch iral sec-
on dary alcoh ols10 an d n um erous ferrocen e ligan ds11, in cludin g fun ction -
alized ferrocen yloxazolin es11b–11e, were successfully used as ch iral catalysts
in th is reaction .
Testin g ch iral oxazolin es 6 as ch iral auxiliaries (2.5 m ole %) in addition
of dieth ylzin c to ben zaldeh yde (Table I, Sch em e 5) revealed th at com -
SCHEME 5
TABLE I
Addition of dieth ylzin c to ben zaldeh ydea
En try
Ligan d
Yield, %
En an atiom er ratiob
1
2
3
4
6c
6d
6g
6h
36
47
62
73
55:45
54:46
55:45
56:44
a
For con dition s, see Experim en tal. Alkylation in th e presen ce of ligan ds 6a an d 6f gave un -
der th e sam e con dition s on ly dark in tractable m ixtures wh ich con tain ed n o 1-ph en yl-
b
propan -1-ol accordin g to GC MS an alysis. Determ in ed by GC MS an alysis after con vertin g
to diastereom eric (–)-m en th oxycarbon yl esters (see Experim en tal). Con figuration was n ot as-
sign ed due to a very low asym m etric in duction .
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Štěpnička et al.:
poun ds 6c, 6d , 6g, an d 6h exh ibit on ly n egligible asym m etric in duction ,
wh ilst 6a an d 6f gave un der iden tical con dition s in tractable m ixtures con -
tain in g n o 1-ph en ylpropan -1-ol accordin g to GC-MS an alysis. Th e observed
poor catalytic activity of th e oxazolin es con trasts sh arply with th e previous
reports about a very h igh efficien cy of ch iral, fun ction alized ferrocen yl-
oxazolin es in th is reaction 6,11 an d m ost likely reflects a h in dered
accessibility of th e don or n itrogen atom s, in accordan ce with difficulties en -
countered in th e alkylation of am in es 2 (see above).
Structure Determ in ation for 2b an d 2g
Structures of am in es 2b an d 2g were determ in ed by sin gle-crystal X-ray dif-
fraction . Th e m olecular structures are sh own in Figs 1 an d 2 an d th e se-
lected geom etric data are reported in Tables II an d III. Th e structures sh ow
n o un expected features, th e in dividual bon d an d an gles com parin g well
with th ose reported for th e un substituted am in e FcCH2NHPh ; cf.
C(Fc)–C(11) 1.508(5), N–CH2 1.438(4), an d N–C(Ph ) 1.387(4) Å 12
.
Am in e 2b crystallizes with two crystallograph ically in depen den t m ole-
cules with in th e triclin ic un it cell. Th e m olecules sh ow n early iden tical
bon d distan ces an d an gles but differ sligh tly in th e m utual orien tation of
FIG. 1
A view of th e m olecular structure of 2b, m olecule 1 sh owin g th e th erm al m otion ellipsoids at
th e 30% probability level an d th e atom labellin g sch em e
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Spaced Ferrocene Oxazolines
1213
th e ph en yl an d substituted cyclopen tadien yl plan es. Th e dih edral an gle of
th e respective least-squares plan es are 52.9(2) (44.7(2)°) for m olecules 1 (2).
As indicated by the torsion angles τ(C(Ar)–N–CH2–C(Fc)) of 176.9(2) (–173.6(3)°),
TABLE II
Selected bon d len gth s (Å), bon d an gles an d dih edral an gles (°) for 2b
Molecule 1
Molecule 2
N1–C11
N1–C12
C01–C11
C13–C18
1.457(3)
1.389(3)
1.500(4)
1.505(4)
N2–C31
N2–C32
C21–C31
C33–C38
1.446(3)
1.382(3)
1.497(3)
1.506(4)
C11–N1–C12
N1–C11–C01
N1–C12–C13
N1–C12–C17
120.4(2)
C31–N2–C32
N2–C31–C21
N2–C32–C33
N2–C32–C37
123.2(2)
110.9(2)
119.4(2)
121.6(2)
110.6(2)
119.2(2)
121.9(2)
Fe–C(Cp) av.
C–C(Cp) av.
C–C(Ph ) av.
2.047(6)
2.045(5)
1.421(5)
1.39(1)
1.421(6)
1.39(1)
C–C–C(Cp) av.
C–C–C(Ph ) av.
108.0(3)
120(1)
108.0(3)
120(1)
FIG. 2
Th e m olecular structure of am in e 2g drawn with 30% th erm al m otion ellipsoids
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

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Štěpnička et al.:
th e ferrocen yl an d ph en yl substituen ts adopt an an tiperiplan ar con figura-
tion , sim ilar to th e arran gem en t of am in e FcCH2NHPh (cf. τ = 179.4(3)°,
in terplan ar an gle 35.9(2)°). Th e ferrocen e cyclopen tadien yls in 2b exh ibit
on ly in sign ifican t tilts (in terplan ar an gles 3.2(2) (1.0(2)°)) an d are bon ded
TABLE III
Selected bon d len gth s (Å), bon d an gles an d dih edral an gles (°) for 2g
C1–C11
N–C11
N–C12
Cl–C15
1.498(2)
1.455(2)
1.375(2)
1.749(2)
C2–C1–C11
C5–C1–C11
N–C11–C1
C11–N–C12
126.9(2)
125.7(2)
109.2(1)
123.8(2)
N–C12–C13
N–C12–C17
122.8(2)
119.2(2)
Cl–C15–C14
Cl–C15–C16
119.8(1)
119.1(1)
Fe–C(Cp) av.
C–C(Cp) av.
C–C(Ph ) av.
2.040(7)
C–C–C(Cp) av.
C–C–C(Ph ) av.
108.0(6)
120(1)
1.42(1)
1.39(1)
FIG. 3
Solid state packin g of 2b as viewed alon g th e crystallograph ic b axis
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Spaced Ferrocene Oxazolines
1215
at iden tical iron –rin g distan ces Fe–Cg1 1.651(1) (1.651(1) Å), and Fe–Cg2
1.653(2) (1.649(2) Å) (Cg denotes the respective cyclopentadienyl-rin g cen -
troid).
As far as bon d len gth s an d an gles are con cern ed, th e structure of am in e
2g does n ot differ m uch from FcCH2NHPh an d 2b. Th e cyclopen tadien yl
plan es are tilted at an an gle of 2.02(4)° an d th e iron -rin g cen troid distan ces
are Fe–Cg(1) 1.6433(8) an d Fe–Cg(2) 1.6477(9) Å. Th e m olecule, h owever,
differs sligh tly from th e referen ce com poun ds in con form ation . Th e aren e
an d th e substituted cyclopen tadien yl plan es are n early perpen dicular (di-
h edral an gle 85.08(6)°) an d th e con figuration at th e N–CH2 bon d sligh tly
departs from an tiperiplan ar towards an ticlin al (τ = 164.1(2)°).
Th e solid-state packin gs of 2b an d 2g are m olecular with out an y apparen t
in volvem en t of th e NH groups in h ydrogen bon din g. In both cases, h ow-
ever, th e m olecular assem bly is aided with offset π–π in teraction s of th e
ph en yl rin gs an d weak C–H···π-rin g in teraction s. In th e case of am in e 2g,
th e m olecules are orien ted so th at th e exactly parallel ph en yl rin gs are
stacked in to tilted colum n s at rin g cen troid distan ces of 5.850(1) Å an d
in terplan ar separation of 3.71 Å (Fig. 3). A sim ilar in teraction is observed
also for 2b th ough with even closer con tan cts: rin g cen troid distan ce
5.541(2) Å, in terplan ar separation 3.03 Å.
2-[{N-Benzyl-N-(ferrocenylmethyl)amino}methyl]oxazolines
In order to prove our assum ption th at th e steric in accessibility of th e n itro-
gen atom in am in es 2 h am pers th e alkylation reaction an d, m ore im por-
tan tly, results in th e very low catalytic efficien cy of oxazolin es 5 an d 6, we
h ave syn th esized ben zyl(ferrocen ylm eth yl)am in es 8a, 8b an d furth er con -
verted to am m on ium salt 9 an d oxazolin e 10, respectively (Sch em e 6),
wh ich were ch aracterized by X-ray crystallograph y (see below).
Sch iff bases 7 an d am in es 8 were obtain ed usin g th e procedures described
for th e preparation of 1 an d 2. Th e IR an d NMR spectra of 7 an d 8 corre-
spon d well to th e spectra of com poun ds 1 an d 2; h owever, th e com poun ds
differ in th e m ass spectra. Th e Sch iff bases 7a an d 7b fragm en t by a loss of a
[C5H6] fragm en t (possibly [C5H5 + H]) or th e correspon din g ben zyl cation s
([C7H7]+ an d [C7H7Me]+ for 7a an d 7b, respectively) from th e m olecular
ion s. Furth erm ore, th e spectra sh ow abun dan t sign als due to “[FcCH2]+”,
Fc+ (rath er th an [FcH]• +, see above), Fe+, an d th e ben zyl cation s (m/z 91 an d
105, respectively). Wh ereas th e fragm en tation path ways observed for Sch iff
bases 7a an d 7b are sim ilar, th e in itial fragm en tation steps of am in es 8a
an d 8b differ. Th e m olecular ion s fragm en t, respectively, by a loss of a
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

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Štěpnička et al.:
cyclopen tadien e m olecule (8b• + → m/z 253) or [C5H7]• + (likely C5H6 + H+;
8a• + → m/z 238), an d an elim in ation of ben zyl cation (8b• + → m/z 214) or
ben zyl cation togeth er with two h ydrogen atom s (8a• + → m/z 212). Th e
+
oth er im portan t ion ic species (Ph CH2 for 8a; Ph CH(Me)+, Ph H• + an d Ph +
for 8b) an d th e ferrocen e fragm en ts (“[FcCH2]+”, [FcH]• +, [FeC5H5]+, an d
Fe+) are com m on to both spectra.
SCHEME 6
Subsequen t akylation of 7a with excess MeI in th e presen ce of K2CO3
sm ooth ly afforded th e doubly m eth ylated am m on ium salt 9 in virtually
quan titative yield. Oxazolin e 10 was obtain ed by alkylation of 7b with 4b
in th e presen ce of a base as given above. In electron -im pact m ass spectra,
th e m olecular ion 10• + elim in ates a cyclopen tadien yl radical (→ m/z 379),
Ph CH(Me)+ cation (→ m/z 339) or th e oxazolin e substituen t togeth er with
on e h ydrogen atom (→ m/z 317). Th e latter process gen erates ion s isobaric
with [7b]• +, wh ich fragm en t sim ilarly to th e ion s resultin g by ion ization of
th e Sch iff base.
Crystal Structures of 9 an d 10
Th e structure of am m on ium salt 9 is sh own in Fig. 4 an d th e selected geo-
m etric param eters are listed in Table IV. Com pared to th e solid-state struc-
ture of an an alogous am in e, FcCH2NHCH2(C6H4Me-4)13, com poun d 9
exh ibits sligh tly lon ger N–C distan ces an d, in accordan ce with a com plete
substitution of th e n itrogen atom , th e C–N–C an gles less differen t from th e
values expected for an ideal tetrah edral en viron m en t. Th e solid-state pack-
in g of 9 is m olecular.
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Spaced Ferrocene Oxazolines
1217
TABLE IV
a
Selected in teratom ic distan ces (Å) an d an gles (°) for 9
Fe–Cg1
Fe–Cg2
C1–C11
C14–C15
1.6442(9)
1.654(1)
1.487(3)
1.503(3)
N–C11
N–C12
N–C13
N–C14
1.537(2)
1.498(2)
1.503(3)
1.535(3)
Cp1,Cp2
Ph ,Cp1
C–N–Cb
2.7(1)
N–C11–C1
113.9(2)
113.8(2)
56.9(1)
N–C14–C15
106.7(1)–110.5(2)
a
Cp1, Cp2 are th e cyclopen tadien yl rin gs C1–C5 an d C6–C10, respectively. Cg1 an d Cg2 de-
b
n ote th e correspon din g rin g cen troids. Th e ran ge of C–N–C an gles.
FIG. 4
A view of th e cation in th e structure of 9 with 30% th erm al m otion ellipsoids
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1218
Štěpnička et al.:
The molecular structure of oxazoline 10 is shown in Fig. 5, while the selected
distances and angles are given in Table V. The Flack parameter (Table VI) corro-
borates the unchanged configuration of the chiral centres originating from
(R)-1-ph en yleth ylam in e an d (S)-valin ol. Th e side ch ain in 10 is n early per-
pen dicular to th e ferrocen e un it an d so are both rin gs at its term in i (cf. th e
dih edral an gles: Ph vs Cp(1) 82.9(1)°, Ox vs Cp(1) 79.5(1)°, an d Ox vs Ph
10.0(1)°). Th e n itrogen atom s are located at th e m ore open side of th e
ch ain in a pocket defin ed by th e ferrocen ylm eth yl, isopropyl an d
1-ph en yleth yl groups. Th e oxazolin e rin g is very n early plan ar with th e de-
viation s of th e rin g atom s from th eir least-squares plan e lower th an 0.05 Å.
Th e distan ces an d an gles with in th e rin g do n ot deviate in an y sign ifican t
way from th e values reported for oth er ferrocen yloxazolin es14. Th e solid-
state arran gem en t of 10 is essen tially m olecular; th ere are n o con tacts
sh orter th an th e sum of van der Waals radii between th e m olecules with in
th e crystal.
FIG. 5
Th e m olecular structure of oxazolin e 10. Th e th erm al m otion ellipsoids correspon d to th e 30%
probability level
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

Spaced Ferrocene Oxazolines
1219
Conclusions
We h ave dem on strated a n ovel approach to ch iral oxazolin e ligan ds bear-
in g th e ferrocen yl group as a substituen t. Un fortun ately, th e preparation of
ch iral ferrocen yloxazolin es 6 suffers from difficulties in th e m olecule-
assem blin g step an d th e resultin g oxazolin es are n early in active as ch iral
auxiliaries in th e addition of dieth ylzin c to ben zaldeh yde. Th is was ten ta-
tively ascribed to steric bulk of am in es 2 an d oxazolin es 5 an d 6, wh ich
h in ders th e alkylation reaction an d preven ts effective en coun ters between
th e substrate, reagen t, an d oxazolin e catalyst. As dem on strated by alkyl-
TABLE V
a
Selected bon d len gth s (Å) an d an gles (°) for 10
Fe–Cg1
Fe–Cg2
1.6573(9)
1.649(1)
Cp1,Cp2
0.6(1)
C1–C11
C11–N1
N1–C19
C19–C20
C19–C21
N1–C12
C12–C13
1.518(3)
1.465(2)
1.474(2)
1.531(3)
1.520(2)
1.453(3)
1.502(3)
C1–C11–N1
C11–N1–C12
C11–N1–C19
C12–N1–C19
N1–C19–C20
N1–C19–C21
N1–C12–C13
111.2(2)
111.6(2)
112.9(2)
117.1(2)
111.1(2)
108.3(1)
117.6(2)
C13–O
1.369(2)
1.449(3)
1.530(3)
1.486(3)
1.268(3)
1.543(3)
1.529(3)
1.523(4)
N2–C13–O
118.1(2)
105.6(2)
104.4(2)
104.2(2)
106.9(2)
111.3(2)
110.3(2)
116.2(2)
O–C14
C13–O–C14
O–C14–C15
C14–C15–N2
C15–N2–C13
C17–C16–C18
N2–C15–C16
C14–C15–C16
C14–C15
C15–N2
N2–C13
C15–C16
C16–C17
C16–C18
C1–C11–N1–C12
C1–C11–N1–C19
C11–N1–C19–C20
–72.2(2)
153.5(2)
–176.9(2)
a
Cp1, Cp2 den ote th e cyclopen tadien yl rin gs C1–C5 an d C6–C10, respectively. Cg1 an d
Cg2 are th e respective rin g cen troids.
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

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Spaced Ferrocene Oxazolines
1221
ation reaction s of am in es 8, th e difficulties in th e syn th esis can be circum -
ven ted by an in troduction of a m eth ylen e (or an alogous) spacer between
th e n itrogen atom an d th e ph en yl group. Th is in dicates a direction for a
furth er work.
EXPERIMENTAL
All syn th eses were carried un der argon blan ket with exclusion of th e direct dayligh t. Tolu-
en e an d xylen e were dried by stan din g with potassium m etal an d distilled un der argon .
Meth an ol was dried with sodium an d fresh ly distilled. Halogen ated solven ts (CCl4, CHCl3,
CH2Cl2) were dried over an h ydrous potassium carbon ate. Solven ts for crystallization s an d
ch rom atograph y were used with out purification . Oth er ch em icals were used as obtain ed
from com m ercial sources.
NMR spectra were recorded on a Varian UNITY In ova 400 spectrom eter (1H, 399.95; 13C,
100.58 MHz) at 298 K. Ch em ical sh ifts (δ, ppm ) are given relative to in tern al tetram eth yl-
silan e, couplin g con stan ts (J) are given in Hz. NMR sign als were assign ed with th e aid of
1H,1H-COSY, 13C APT, 13C gHSQC an d 13C gHMBC experim en ts. For clarity, th e sym bol Ox
in dicates an oxazolin yl m oiety (e.g., in i-PrOx, Me2Ox); CH2Ox th us den otes th e m eth ylen e
Ox
group attach ed to th e oxazolin e rin g wh ile CHOx an d CH2
stan d for th e m eth in e an d
m eth ylen e groups, respectively, within th e rin g. IR spectra (ν, cm –1) were recorded on an FT
IR Nicolet Magn a 650 in strum en t in th e ran ge of 400–4000 cm –1. Meltin g poin ts were deter-
m in ed on a Kofler apparatus an d are un corrected.
Electron ion ization m ass spectra were recorded on a VG 7070E spectrom eter (con dition s:
electron en ergy 80 eV, ion source tem perature 200 °C). Th e sam ples were in troduced via a
direct in sertion probe. Accurate m ass (HR MS) m easurem en ts were perform ed by th e peak
m atch in g tech n ique usin g perfluorokerosen e as th e in tern al m ass scale stan dard. GC MS
were perform ed on a Fin n igan MAT INCOS 50 m ass spectrom eter in terfaced to a Varian
3400 gas ch rom atograph (SPB-5 capillary colum n , He carried gas). Th e m ass spectra were ac-
quired at ion izin g electron en ergy 70 eV.
Syn th esis of Sch iff Bases 1a–1h . Gen eral Procedure
Ferrrocen ecarboxaldeh yde an d th e appropriate an ilin e (m olar ratio 1:1) were dissolved in
dry toluen e (50 m l). Catalytic am oun t of K2CO3 (5–10 m g) was added, th e reaction vessel
was flush ed with argon , an d th e m ixture was refluxed un der Dean –Stark trap for 24 h . Th en ,
th e reaction m ixture was treated with 4 Å m olecular sieves (ca 25 m l, beads 8–12 m esh )
wh ile h ot an d stirrin g was con tin ued at room tem perature for 48 h . Filtration an d evapora-
tion un der reduced pressure afforded th e correspon din g Sch iff base in pure form .
FcCH=NPh (1a). Startin g from FcCHO (4.92 g, 23 m m ol) an d an ilin e (2.10 m l, 23 m m ol),
th e gen eral procedure gave 1a as an oran ge solid (4.07 g, 91%). EI MS, m/z (relative abun -
dan ce): 290 (21), 289 (100, M• +), 288 (8), 287 (9), 224 (27, [M – C5H5]+), 223 (12), 222 (8),
214 (11), 198 (9), 196 (5), 186 (21, [FcH]• +), 184 (6), 168 (16, [M – C5H5Fe]+), 167 (10), 141
(9), 129 (8), 121 (31, [C5H5Fe]+), 115 (7), 97 (5), 95 (7), 85 (5), 83 (5), 81 (7), 77 (15, Ph +),
73 (9), 71 (7), 70 (30), 69 (8), 65 (4), 60 (9), 57 (12), 56 (34, Fe+). IR (Nujol): 1620 (s), 1585
(s), 1466 (vs), 1252 (m ), 1169 (m ), 1103 (m ), 1005 (m ), 820 (m ), 766 (s), 695 (s), 513 (m ),
496 (s), 485 (m ). For NMR data see ref.12
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

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Štěpnička et al.:
FcCH=NC6H4Me-2 (1b). Startin g from FcCHO (5.79 g, 27 m m ol) an d o-toluidin e (2.89 m l,
27 m m ol), th e gen eral procedure afforded 1b as an oran ge solid (5.59 g, 68%). M.p. 106–108 °C
(ref.6c 122–126 °C). 1H NMR (CDCl3): 2.33 (s, 3 H, Me), 4.23 (s, 5 H, C5H5), 4.47, 4.80 (2 ×
apparen t t, 2 H, C5H4); 6.82–7.22 (m , 4 H, C6H4), 8.21 (s, 1 H, CH=N). 13C NMR (CDCl3):
17.84 (Me), 68.96 (CH, C5H4), 69.27 (C5H5), 71.07 (CH, C5H4), 80.75 (Cipso, C5H4), 117.96,
124.87, 126.71, 130.14 (CH, C6H4); 130.89, 152.18 (Cipso, C6H4); 160.44 (CH=N). EI MS, m/z
(relative abun dan ce): 304 (22), 303 (100, M• +), 302 (12), 301 (22), 238 (24, [M – C5H5]+), 237
(17), 236 (7), 235 (8), 212 (5), 208 (7), 186 (31, [FcH]• +), 184 (5), 182 (9, [M – C5H5Fe]+), 181
(9), 180 (11), 165 (6), 121 (25, [C5H5Fe]+), 92 (13), 91 (64, [C7H7]+), 65 (15), 56 (32, Fe+). IR
(Nujol): 1626 (vs), 1591 (s), 1248 (m ), 1218 (m ), 1180 (m ), 1111 (m ), 1105 (s), 1040 (s), 967
(m ), 824 (s), 806 (m ), 754 (vs), 731 (s), 498 (s), 485 (s). For C18H17FeN (302.4) calculated:
71.30% C, 5.66% H, 4.62% N; foun d: 71.50% C, 5.83% H, 4.42% N.
FcCH=NC6H4Me-3 (1c). Startin g from FcCHO (1.99 g, 9.3 m m ol) an d m-toluidin e (1.00 m l,
9.3 m m ol), th e procedure as above gave 1c as an oran ge solid (2.26 g, 80%). M.p. 54–56 °C.
1H NMR (CDCl3): 2.38 (s, 3 H, Me), 4.23 (s, 5 H, C5H5), 4.46, 4.78 (2 × apparen t t, 2 H,
C5H4); 6.92–7.27 (m , 4 H, C6H4), 8.31 (s, 1 H, CH=N). 13C NMR (CDCl3): 21.43 (Me), 69.00
(CH, C5H4), 69.24 (C5H5), 71.19 (CH, C5H4), 80.50 (Cipso, C5H4), 117.55, 121.39, 125.94,
128.91 (CH, C6H4); 138.86, 152.85 (Cipso, C6H4); 161.02 (CH=N). EI MS, m/z (relative abun -
dan ce): 304 (19), 303 (100, M• +), 302 (12), 301 (10), 238 (26, [M – C5H5]+), 237 (14), 236 (5),
214 (8), 212 (15), 186 (10, [FcH]• +), 184 (8), 182 (11), 180 (7), 152 (5), 152 (5), 129 (9), 121
(41, [C5H5Fe]+), 92 (7), 91 (22, [C7H7]+), 65 (13), 57 (7), 56 (31, Fe+). IR (Nujol): 1620 (vs),
1582 (vs), 1462 (vs), 1238 (m ), 1152 (m ), 1107 (m ), 1043 (m ), 1003 (m ), 930 (m ), 820 (s),
783 (s), 695 (s), 514 (m ), 502 (s), 484 (s). For C18H17FeN (302.4) calculated: 71.30% C, 5.66% H,
4.62% N; foun d: 70.91% C, 5.57% H, 4.48% N.
FcCH=NC6H4Me-4 (1d ). Startin g from FcCHO (5.56 g, 26 m m ol) an d p-toluidin e (2.81 g,
26.2 m m ol), com poun d 1d was obtain ed as an oran ge solid (7.16 g, 91%). M.p. 87–89 °C
(ref.6c 130–132 °C). 1H NMR (CDCl3): 2.35 (s, 3 H, Me), 4.23 (s, 5 H, C5H5), 4.46, 4.78 (2 ×
apparen t t, 2 H, C5H4); 7.06, 7.16 (2 × d, 2 H, C6H4); 8.32 (s, 1 H, CH=N). 13C NMR (CDCl3):
20.96 (Me), 68.97 (CH, C5H4), 69.23 (C5H5), 71.16 (CH, C5H4), 80.58 (Cipso, C5H4), 120.49,
129.70 (CH, C6H4); 134.88, 150.30 (Cipso, C6H4); 160.57 (CH=N). EI MS, m/z (relative abun -
dan ce): 304 (26), 303 (100, M• +), 302 (14), 301 (10), 239 (6), 238 (31, [M – C5H5]+), 237 (17),
236 (5), 212 (9), 211 (5), 210 (10), 186 (11, [FcH]• +), 182 (10, [M – C5H5Fe]+), 181 (9), 155
(5), 154 (5), 153 (6), 152 (5), 129 (7), 121 (15, [C5H5Fe]+), 92 (6), 91 (17, [C7H7]+), 83 (5), 73
(13), 71 (9), 69 (8), 65 (11), 60 (10), 57 (14), 56 (28, Fe+). IR (Nujol): 1618 (vs), 1591 (vs),
1509 (s), 1326 (m ), 1250 (m ), 1188 (m ), 1106 (s), 1044 (s), 1024 (s), 1003 (s), 818 (vs), 635
(m ), 527 (m ), 519 (m ), 513 (m ), 487 (vs), 478 (vs). For C18H17FeN (302.4) calculated: 71.30% C,
5.66% H, 4.62% N; foun d: 71.42% C, 5.69% H, 4.57% N.
FcCH=NC6H4OMe-4 (1e). Usin g th e gen eral procedure, FcCHO (5.24 g, 24.5 m m ol) an d
p-an isidin e (3.02 g, 24.5 m m ol) gave 1e as an oran ge solid (7.40 g, 95%). M.p. 105–107 °C.
1H NMR (CDCl3): 3.81 (s, 3 H, OMe), 4.23 (s, 5 H, C5H5), 4.45, 4.78 (2 × apparen t t, 2 H,
C5H4); 6.87–7.17 (m , 4 H, C6H4), 8.32 (s, 1 H, CH=N). 13C NMR (CDCl3): 55.48 (OMe), 68.85
(CH, C5H4), 69.20 (C5H5), 71.06 (CH, C5H4), 80.76 (Cipso, C5H4), 114.34, 121.68 (CH, C6H4);
145.94, 157.61 (Cipso, C6H4); 159.58 (CH=N). EI MS, m/z (relative abun dan ce): 320 (23), 319
(100, M• +), 318 (6), 317 (8), 304 (12, [M – Me]+), 254 (12, [M – C5H5]+), 253 (8), 239 (7, [M –
Me – C5H5]• +), 238 (6), 198 (5, [M – C5H5Fe]+), 186 (12, [FcH]• +), 184 (5), 160 (7), 155 (6),
154 (7), 149 (6), 129 (9), 128 (5), 121 (30, [C5H5Fe]+), 97 (5), 85 (5), 83 (7), 81 (7), 77 (5), 73
(13), 71 (8), 70 (4), 69 (14), 60 (9), 57 (18), 56 (24, Fe+). IR (Nujol): 1618 (vs), 1593 (m ),
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Spaced Ferrocene Oxazolines
1223
1577 (m ), 1505 (vs), 1464 (vs), 1441 (m ), 1291 (m ), 1244 (vs), 1187 (m ), 1104 (m ), 1030 (s),
833 (vs), 822 (s), 784 (m ), 523 (m ), 504 (m ), 481 (m ). For C18H17FeNO (302.4) calculated:
67.72% C, 5.38% H, 4.39% N; foun d: 67.77% C, 5.43% H, 4.36% N.
FcCH=NC6H4F-4 (1f). Startin g from FcCHO (2.00 g, 9.3 m m ol) an d p-fluoroan ilin e (0.86 m l,
9.1 m m ol), th e procedure as above afforded 1f as an oran ge solid (2.02 g, 71%). M.p. 96–98 °C.
1H NMR (CDCl3): 4.24 (s, 5 H, C5H5), 4.48, 4.78 (2 × apparen t t, 2 H, C5H4); 7.02–7.13 (m , 4 H,
C6H5), 8.30 (s, 1 H, CH=N). 13C NMR (CDCl3): 69.03 (CH, C5H4), 69.27 (C5H5), 71.33 (CH,
2
3
C5H4), 80.33 (Cipso, C5H4), 115.8 (d, JFC = 22, CH, C6H4), 121.9 (d, JFC = 8, CH, C6H4);
4
1
149.00 (d, JFC = 3, CN, C6H4), 160.80 (d, JCF = 243, CF, C6H4); 161.3 (CH=N). EI MS, m/z
(relative abun dan ce): 308 (22), 307 (100, M• +), 306 (9), 305 (7), 242 (12, [M – C5H5]+), 241
(17), 240 (5), 216 (7), 214 (9), 187 (6), 186 (57, [M – C5H5Fe]+ an d [FcH]• +), 185 (9), 184
(16), 166 (6), 149 (8), 141 (7), 140 (11), 139 (17), 129 (13), 128 (6), 122 (5), 121 (47,
[C5H5Fe]+), 119 (5), 115 (7), 111 (6), 109 (5), 97 (12), 95 (13), 85 (8), 83 (11), 82 (5), 81 (11),
81 (5), 77 (5), 75 (5), 73 (15), 71 (16), 70 (7), 69 (18), 67 (7), 65 (12), 60 (13), 57 (22), 56
(49, Fe+). IR (Nujol): 1622 (vs), 1502 (s), 1209 (s), 1186 (s), 1104 (m ), 1090 (m ), 1047 (m ),
833 (s), 820 (m ), 808 (m ), 791 (s), 536 (m ), 500 (s), 479 (s). For C17H14FFeN (306.4) calcu-
lated: 66.47% C, 4.60% H, 4.56% N; foun d: 66.32% C, 4.59% H, 4.40% N.
FcCH=NC6H4Cl-4 (1g). Startin g from FcCHO (6.49 g, 30.3 m m ol) an d p-ch loroan ilin e
(3.82 g, 30 m m ol), th e gen eral procedure gave 1g as an oran ge solid (7.98 g, 81%). M.p.
98–100 °C. 1H NMR (CDCl3): 4.24 (s, 5 H, C5H5), 4.50, 4.78 (2 × apparen t t, 2 H, C5H4);
7.04–7.34 (m , 4 H, C6H4), 8.30 (s, 1 H, CH=N). 13C NMR (CDCl3): 69.11 (CH, C5H4), 69.31
(CH, C5H5), 71.48 (CH, C5H4), 80.11 (Cipso, C5H4), 121.91, 129.16 (CH, C6H4); 130.60,
151.36 (Cipso, C6H4); 161.85 (CH=N). EI MS, m/z (relative abun dan ce): 325 (19), 324 (13),
323 (57, M• +), 258 (11, [M – C5H5]+), 257 (7), 232 (6), 214 (19), 202 (4, [M – C5H5Fe]+), 187
(7), 186 (55, [FcH]• +), 184 (9), 167 (13), 166 (11), 140 (6), 139 (11), 129 (6), 121 (38,
[C5H5Fe]+), 115 (5), 94 (5), 93 (6), 92 (49), 91 (100), 81 (6), 69 (8), 65 (14), 63 (8), 60 (5), 57
(10), 56 (32, Fe+). IR (Nujol): 1617 (vs), 1579 (m ), 1491 (m ), 1464 (vs), 1252 (m ), 1213 (m ),
1172 (m ), 1107 (m ), 1008 (m ), 841 (m ), 830 (s), 822 (s), 522 (m ), 515 (m ), 501 (s), 480 (m ),
437 (m ). For C17H14ClFeN (322.8) calculated: 63.09% C, 4.37% H, 4.33% N; foun d: 63.37% C,
4.62% H, 4.19% N.
FcCH=NC6H4Br-4 (1h ). Startin g from FcCHO (2.00 g, 9.3 m m ol) an d p-brom oan ilin e
(1.31 g, 7.6 m m ol), th e gen eral procedure gave 1h as an oran ge solid (1.95 g, 57%). M.p.
113–115 °C. 1H NMR (CDCl3): 4.24 (s, 5 H, C5H5), 4.50, 4.78 (2 × apparen t t, 2 H, C5H4);
6.98–7.49 (m , 4 H, C6H4), 8.30 (s, 1 H, CH=N). 13C NMR (CDCl3): 69.13 (CH, C5H4), 69.32
(C5H5), 71.50 (CH, C5H4), 80.11 (Cipso, C5H4), 118.39 (CBr, C6H4), 122.33, 132.11 (CH,
C6H4); 151.86 (Cipso, C6H4), 161.88 (CH=N). EI MS, m/z (relative abun dan ce): 367 (4, M• +),
214 (27), 186 (19, [FcH]• +), 184 (5), 149 (5), 129 (9), 121 (28, [C5H5Fe]+), 115 (5), 97 (8), 95
(6), 92 (22), 91 (47), 85 (10), 83 (12), 82 (5), 81 (14), 77 (5), 73 (17), 71 (14), 70 (7), 69 (21),
67 (6), 65 (10), 61 (5), 60 (18), 57 (31), 56 (37, Fe+). IR (Nujol): 1691 (m ), 1616 (vs), 1577 (s),
1490 (s), 1464 (vs), 1412 (m ), 1251 (m ), 1212 (s), 1172 (s), 1107 (s), 1072 (s), 1044 (m ), 1024
(m ), 1005 (s),846 (m ), 821 (vs), 634 (m ), 514 (s), 498 (s), 480 (s). For C17H14BrFeN (367.3)
calculated: 55.47% C, 3.84% H, 3.81% N; foun d: 56.07% C, 3.93% H, 3.36% N.
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1224
Štěpnička et al.:
Syn th esis of Am in es 2a–2h . Gen eral Procedure
Solid NaBH4 (4 m olar equiv.) was slowly added in to an ice-cooled solution of Sch iff bases
1a–1h in dry MeOH (25 m l) with stirrin g (in air). After stirrin g for 1 h , aqueous 1 M NaOH
solution (30 m l) was added an d th e product was extracted in to ch loroform (3 × 50 m l).
Dryin g of th e com bin ed organ ic ph ase (MgSO4) followed by evaporation un der vacuum af-
forded pure am in es 2a–2h .
FcCH2NHPh (2a). Startin g from 1a (1.74 g, 6 m m ol) an d NaBH4 (0.91 g, 24 m m ol), th e
gen eral procedure gave 2a as a yellow solid (1.28 g, 73%). EI MS, m/z (relative abun dan ce):
292 (9), 291 (45, M• +), 213 (7, [M – Ph H]• +), 200 (18), 199 (100, [C11H11Fe]+), 198 (4), 197
(8), 186 (11, [FcH]• +), 122 (5), 121 (52, [C5H5Fe]+), 93 (24, [Ph NH2]• +), 92 (14), 91 (17), 85
(20), 83 (26), 77 (7), 69 (9), 66 (7), 65 (7), 57 (5), 56 (27, Fe+). HR MS: for C17H17FeN calcu-
lated 291.0710, foun d 291.0690. IR (Nujol): 3401 (s), 1604 (s), 1505 (s), 1428 (s), 1331 (m ),
1317 (s), 1255 (m ), 1180 (m ), 1105 (s), 999 (m ), 866 (m ), 826 (m ), 808 (m ), 748 (s), 693 (s),
491 (s). For oth er ch aracterization data see ref.12
FcCH2NHC6H4Me-2 (2b ). Startin g from 1b (0.91 g, 3 m m ol) an d NaBH4 (0.46 g, 12.2
m m ol), th e gen eral procedure gave 2b as a yellow solid (0.83 g, 92%). 1H NMR (CDCl3):
2.20 (s, 3 H, Me), 3.81 (s, 1 H, NH), 3.97 (s, 2 H, CH2), 4.17 (apparen t t, 2 H, C5H4), 4.20 (s,
5 H, C5H5), 4.28 (apparen t t, 2 H, C5H4), 6.65–7.19 (m , 4 H, C6H4). 13C NMR (CDCl3): 17.57
(Me), 42.99 (CH2), 67.87, 67.93 (CH, C5H4); 68.48 (C5H5), 86.70 (Cipso, C5H4), 109.71, 117.02
(CH, C6H4); 121.68 (Cipso, C6H4), 127.23, 130.09 (CH, C6H4); 146.19 (Cipso, C6H4). EI MS, m/z
(relative abun dan ce): 306 (6), 305 (30, M• +), 200 (12), 199 (100, [C11H11Fe]+), 197 (6), 161
(4), 121 (37, [C5H5Fe]+), 106 (5), 91 (4), 69 (4), 56 (17, Fe+). HR MS: for C18H19FeN calcu-
lated 305.0867, foun d 305.0874. IR (Nujol): 3416 (s), 1605 (s), 1582 (m ), 1514 (s), 1503 (s),
1444 (m ), 1314 (m ), 1260 (m ), 1133 (m ), 1104 (s), 1025 (m ), 1002 (m ), 924 (m ), 830 (m ),
815 (m ), 749 (s), 495 (m ), 487 (m ), 444 (m ).
FcCH2NHC6H4Me-3 (2c). Startin g from 1c (1.57 g, 5.2 m m ol) an d NaBH4 (1.12 g, 30 m m ol),
th e gen eral procedure gave 2c as a yellow solid (1.43 g, 90%). 1H NMR (CDCl3): 2.30 (s, 3 H,
Me), 3.82 (s, 1 H, NH), 3.94 (s, 2 H, CH2), 4.14 (apparen t t, 2 H, C5H4), 4.18 (s, 5 H, C5H5),
4.24 (apparen t t, 2 H, C5H4), 6.45–7.12 (m , 4 H, C6H4). 13C NMR (CDCl3): 21.64 (Me), 43.36
(CH2), 67.85, 68.07 (CH, C5H4); 68.47 (C5H5), 86.59 (Cipso, C5H4), 109.98, 113.57, 118.46,
129.15 (CH, C6H4); 139.06, 148.35 (Cipso, C6H4). EI MS, m/z (relative abun dan ce): 306 (8),
305 (37, M• +), 227 (6), 200 (15), 197 (6), 121 (39, [C5H5Fe]+), 107 (3), 106 (4), 91 (5), 83 (4),
69 (5), 57 (4), 56 (15, Fe+). HR MS: for C18H19FeN calculated 305.0867, foun d 305.0885.
IR (Nujol): 3410 (vs), 1603 (s), 1588 (m ), 1509 (s), 1306 (s), 1256 (m ), 1166 (m ), 1104 (m ),
992 (m ), 926 (m ), 817 (s), 775 (s), 693 (m ), 505 (m ), 487 (m ).
FcCH2NHC6H4Me-4 (2d ). Startin g from 1d (1.82 g, 6 m m ol) an d NaBH4 (0.91 g, 24 m m ol),
th e gen eral procedure gave 2d as a yellow solid (1.70 g, 93%). 1H NMR (CDCl3): 2.25 (s, 3 H,
Me), 3.73 (s, 1 H, NH), 3.93 (s, 2 H, CH2), 4.12 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5),
4.23 (apparen t t, 2 H, C5H4), 6.56–7.03 (m , 4 H, C6H4). 13C NMR (CDCl3): 20.41 (Me), 43.75
(CH2), 67.82, 68.07 (CH, C5H4); 68.45 (C5H5), 86.69 (Cipso, C5H4), 113.03 (CH, C6H4), 126.72
(Cipso, C6H4), 129.75 (CH, C6H4), 146.10 (Cipso, C6H4). EI MS, m/z (relative abun dan ce): 306
(6), 305 (29, M• +), 227 (3), 200 (13), 197 (5), 186 (9, [FcH]• +), 121 (42, [C5H5Fe]+), 106 (5),
91 (5), 69 (3), 56 (14, Fe+). HR MS: for C18H19FeN calculated 305.0867, foun d 305.0854.
IR (Nujol): 3395 (s), 1611 (s), 1521 (vs), 1404 (m ), 1317 (s), 1304 (m ), 1252 (s), 1185 (m ),
1125 (m ), 1104 (s), 1034 (m ), 820 (m ), 811 (m ), 522 (m ), 511 (s), 499 (m ), 483 (s).
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

Spaced Ferrocene Oxazolines
1225
FcCH2NHC6H4OMe-4 (2e). Startin g from 1e (1.92 g, 6 m m ol) an d NaBH4 (0.91 g, 24 m m ol),
th e gen eral procedure gave 2e as a yellow solid (1.60 g, 83%). 1H NMR (CDCl3): 3.52 (s, 1 H,
NH), 3.74 (s, 3 H, OMe), 3.91 (s, 2 H, CH2), 4.12 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5),
4.22 (apparen t t, 2 H, C5H4), 6.59–6.82 (m , 4 H, C6H4). 13C NMR (CDCl3): 44.41 (CH2),
55.80 (OMe), 67.81, 68.07 (CH, C5H4); 68.44 (CH, C5H5), 86.66 (Cipso, C5H4), 114.19, 114.91
(CH, C6H4); 142.61, 152.22 (Cipso, C6H4). EI MS, m/z (relative abun dan ce): 322 (4), 321 (21,
M• +), 319 (5), 228 (4), 214 (5), 200 (14), 199 (100, [C11H11Fe]+), 197 (6), 123 (34,
[MeOC6H4NH2]• +), 121 (48, [C5H5Fe]+), 108 (47), 80 (22), 65 (5), 57 (5), 56 (17, Fe+). HR MS:
for C18H19FeNO calculated 321.0816, foun d 321.0747. IR (Nujol): 3367 (s), 1512 (s), 1408
(m ), 1298 (m ), 1248 (m ), 1233 (s), 1180 (m ), 1105 (m ), 1037 (m ), 1002 (m ), 814 (s), 773 (m ),
504 (m ), 486 (m ), 447 (m ).
FcCH2NHC6H4F-4 (2f). Startin g from 1f (1.73 g, 5.63 m m ol) an d NaBH4 (0.89 g, 24 mmol),
th e gen eral procedure gave 2f as a yellow solid (1.63 g, 94%). 1H NMR (CDCl3): 3.75 (s, 1 H,
NH), 3.92 (s, 2 H, CH2), 4.14 (apparen t t, 2 H, C5H4), 4.18 (s, 5 H, C5H5), 4.23 (apparen t t, 2 H,
C5H4), 6.55–6.94 (m , 4 H, C6H4). 13C NMR (CDCl3): 44.13 (CH2), 67.94, 68.11 (CH, C5H4),
3
2
68.50 (CH, C5H5), 86.29 (Cipso, C5H4), 113.65 (d, JFC = 8, CH, C6H4), 115.68 (d, JFC = 22,
4
1
CH, C6H4), 144.69 (d, JFC = 2, CN, C6H4), 155.90 (d, JFC = 235, CF, C6H4). EI MS, m/z (rela-
tive abun dan ce): 310 (6), 309 (31, M• +), 200 (13), 199 (100, [C11H11Fe]+), 197 (6), 186 (3,
[FcH]• +), 122 (4), 121 (41, [C5H5Fe]+), 69 (6), 57 (4), 56 (19, Fe+). HR MS: for C17H16FFeN cal-
culated 309.0616, foun d 309.0575. IR (Nujol): 3409 (s), 1604 (m ), 1507 (s), 1402 (m ), 1314
(m ), 1250 (m ), 1210 (s), 1154 (m ), 1102 (s), 1036 (m ), 824 (s), 788 (m ), 514 (s), 499 (m ), 482
(s).
FcCH2NHC6H4Cl-4 (2g). Startin g from 1g (1.94 g, 6 m m ol) an d NaBH4 (0.91 g, 24 m m ol),
th e above procedure afforded 2g as a yellow solid (1.84 g, 99%). 1H NMR (CDCl3): 3.88 (s,
1 H, NH), 3.92 (s, 2 H, CH2), 4.15 (apparen t t, 2 H, C5H4), 4.17 (s, 5 H, C5H5), 4.22 (appar-
en t t, 2 H, C5H4), 6.54–7.16 (m , 4 H, C6H4). 13C NMR (CDCl3): 43.51 (CH2), 67.99, 68.11
(CH, C5H4); 68.51 (CH, C5H5), 86.00 (Cipso, C5H4), 113.85 (CH, C6H4), 122.00 (Cipso, C6H4),
129.08 (CH, C6H4), 146.79 (Cipso, C6H4). EI MS, m/z (relative abun dan ce): 327 (7), 326 (5),
325 (24, M• +), 216 (5), 200 (17), 199 (100, [C11H11Fe]+), 197 (7), 187 (5), 186 (40, [FcH]• +),
138 (10), 129 (18), 128 (5), 127 (54), 122 (5), 121 (64, [C5H5Fe]+), 100 (6), 99 (5), 95 (5), 92
(14), 91 (7), 85 (23), 83 (5), 83 (45), 81 (8), 71 (6), 69 (16), 65 (25), 64 (5), 63 (7), 57 (12), 56
(40, Fe+). HR MS: for C17H1635ClFeN calculated 325.0321, foun d 325.0292. IR (Nujol): 3421
(s), 1595 (s), 1499 (s), 1400 (s), 1320 (s), 1248 (m ), 1185 (m ), 1174 (m ), 1119 (m ), 1103 (s),
1035 (m ), 998 (m ), 821 (s), 636 (m ), 507 (s), 487 (s), 435 (m ).
FcCH2NHC6H4Br-4 (2h ). Followin g th e gen eral procedure, 1h (1.84 m l, 5 m m ol) an d
NaBH4 (1.37 g, 36 m m ol) yielded 2h as a yellow solid (1.86 g, 99%). 1H NMR (CDCl3): 3.90
(s, 1 H, NH), 3.92 (s, 1 H, CH2), 4.15 (apparen t t, 2 H, C5H4), 4.17 (s, 5 H, C5H5), 4.22 (ap-
paren t t, 2 H, C5H4), 6.50–7.29 (m , 4 H, C6H4). 13C NMR (CDCl3): 43.41 (CH2), 68.01, 68.11
(CH, C5H4); 68.52 (C5H5), 85.95 (Cipso, C5H4), 109.01 (Cipso, C6H4), 114.34, 131.96 (CH,
C6H4); 147.19 (Cipso, C6H4). EI MS, m/z (relative abun dan ce): 371 (16, M• +), 370 (4), 369
(17), 200 (16), 199 (100, [C11H11Fe]+), 197 (7), 173 (19), 171 (21), 168 (4), 167 (4), 121 (36,
[C5H5Fe]+), 92 (13), 91 (4), 65 (17), 63 (6), 56 (13, Fe+). HR MS: for C17H1671BrFeN calculated
370.9795, foun d 370.9814. IR (Nujol): 3407 (s), 1592 (s), 1498 (s), 1312 (s), 1176 (m ), 1104
(s), 1070 (m ), 998 (s), 832 (m ), 808 (s), 508 (m ), 495 (s), 485 (s).
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1226
Štěpnička et al.:
Syn th esis of (Hydroxym eth yl)oxazolin es 3
A solution of glycolic acid an d th e respective β-am in oalcoh ol (1 equiv.) in dry xylen e was
refluxed un der Dean –Stark trap for 15 h . After coolin g to room tem perature, th e solven t was
rem oved un der reduced pressure an d th e residue distilled un der vacuum . Th e oxazolin es
were ch aracterized by NMR spectroscopy an d directly used in th e n ext step.
Compound 3a: Yield 12.82 g (50%) at 198 m m ol scale; colourless crystallin e solid. 1H NMR
1
(CDCl3): 1.30 (s, 6 H, Me), 4.01 an d 4.22 (2 × s, 2 H, CH2), 4.63 (br s, 1 H, OH). 13C{ H}
NMR (CDCl3): 28.24 (Me), 56.98 (CH2), 66.69 (CMe2), 79.82 (CH2), 166.84 (C=N).
Compound 3b: Yield 6.28 g (48%) at 92 m m ol scale; colourless crystallin e solid. [α ]2D2 –98
(c 0.51, EtOH), [α ]D22 –60.5 (c 0.99, CHCl3). Ch aracterization data were con sisten t with th e lit-
erature data15 ([α]D –48.5 (c 2.0, CH2Cl2)).
Con version of (Hydroxym eth yl)oxazolin es 3 to (Ch lorom eth yl)oxazolin es 4
Triph en ylph osph in e (25.2 g, 96 m m ol) was added to a solution of oxazolin e 3a (93 m m ol)
in CCl4 (90 m l), an d th e m ixture was refluxed un der argon for 19 h . After coolin g to room
tem perature, th e volatiles were rem oved un der reduced pressure an d th e sem isolid residue
was extracted with h exan e (5 × 100 m l). Th e extracts were com bin ed, h exan e was evapo-
rated an d th e residue distilled un der vacuum (at ca 65 Pa) to give oxazolin e 4a. Oxazolin e
4b was obtain ed sim ilarly from 3a (20.0 g, 140 m m ol), PPh 3 (37.9 g, 145 m m ol) an d CCl4
(150 m l).
Compound 4a: Yield 9.31 g (54%), colourless liquid. 1H NMR (CDCl3): 1.31 (s, 6 H, Me),
4.05 an d 4.09 (2 × s, 2 H, CH2). An alytical data correspon d to th ose publish ed in ref.16
3
Compound 4b: Yield 14.6 g (65%), colourless liquid. 1H NMR (CDCl3): 0.90 (d, JHH = 6.8,
3
3 H, CHMe), 0.98 (d, JHH = 6.8, 3 H, CHMe), 1.70–1.85 (m , 1 H, CHMe2), 3.93–4.02 (m , 1 H,
CHOx), 4.04–4.39 (m , 2 H, CH2ox), 4.12 (s, 2 H, CH2Cl). [α ]D22 –79.6 (c 1.1, CHCl3).
Alkylation of Ferrocen eam in es 2 with Ch lorooxazolin es 4. Gen eral Procedure
Oxazolin es 5 an d 6 were syn th esized by h eatin g a stirred m ixture of am in e 1 (1 m m ol),
oxazolin e 4 (2 m m ol), an d K2CO3 (3 m m o) to 80–90 °C (tem perature in bath ) un der an ar-
gon atm osph ere for 48 h . Th en , th e dark m ixture was cooled to room tem perature an d ex-
tracted in to ch loroform (3 × 5 m l). Th e com bin ed extracts were evaporated an d th e residue
was purified by ch rom atograph y on silica gel usin g ch loroform as th e eluen t. Th e secon d
oran ge ban d was collected, evaporated an d th e residue ch rom atograph ed on ce again on
silica gel colum n with eth yl acetate–h exan e (1:1, v/v). Evaporation an d dryin g in vacuum
(65 Pa, 60 °C, 1 h ) afforded oxazolin es 5, an d 6a, 6c, 6d , 6f–6h , respectively, as dark oran ge
oils in th e yields n ot exceedin g 30%. In oth er cases (6b, 6e), in tractable dark m ixtures were
obtain ed from wh ich n o defin ed product could be isolated.
FcCH2N(CH2Me2Ox)Ph (5). 1H NMR (CDCl3): 1.26 (s, 6 H, Me), 3.91 (s, 2 H, CH2), 4.04 (s,
2 H, CH2), 4.10 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5), 4.22 (apparen t t, 2 H, C5H4),
4.37 (s, 2 H, CH2), 6.70–7.24 (m , 5 H, C6H5). 13C NMR (CDCl3): 28.31 (Me), 46.85, 50.47
(CH2); 67.14 (CMe2Ox), 67.96 (CH, C5H4), 68.61 (C5H5), 69.21 (CH, C5H4), 79.25 (CH2Ox),
83.94 (Cipso, C5H4), 113.42, 117.46, 129.01 (CH, C6H5); 148.57 (Cipso, C6H5), 163.45 (CipsoOx).
EI MS, m/z (relative abun dan ce): 402 (12, M• +), 337 (6, [M – C5H5]+), 291 (6), 290 (37), 289
(100, [1a]• +), 287 (7), 224 (5), 204 (18), 200 (8), 199 (52, [C11H11Fe]+), 187 (9), 132 (9), 121
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Spaced Ferrocene Oxazolines
1227
(31, [C5H5Fe]+), 106 (20), 105 (11), 104 (10), 77 (12), 56 (11, Fe+). HR MS: for C23H26FeN2O
calculated 402.1395, foun d 402.1385.
3
(S)-FcCH2N(CH2i-PrOx)Ph (6a ). 1H NMR (CDCl3): 0.86, 0.93 (2 × d, JHH = 6.8, 3 H,
Ox
CHMe2); 1.70–1.82 (m , 1 H, CHMe2), 3.89–3.98 (m , 2 H, CH2
an d CHOx), 4.08 (bs, 2 H,
CH2Ox), 4.10 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5), 4.16–4.24 (m , 3 H, C5H4 an d
CH2Ox), 4.35, 4.39 (2 × d, JHH = 15.4, 1 H, AB system of FcCH2); 6.69–7.24 (m , 5 H, C6H5).
2
13C NMR (CDCl3): 17.98, 18.76 (CHMe2); 32.34 (CHMe2), 46.53 (CH2Ox), 50.39 (FcCH2),
67.94 (CH, C5H4), 68.62 (C5H5), 69.13 (CH, C5H4), 70.03 (CH2Ox), 71.96 (CHOx), 84.00
(Cipso, C5H4), 113.41, 117.44, 129.02 (CH, C6H5); 148.54 (Cipso, C6H5), 164.81 (CipsoOx). EI MS,
m/z (relative abun dan ce): 416 (10, M• +), 351 (5, [M – C5H5]+), 291 (9), 290 (37), 289 (100,
[1a]• +), 287 (6), 200 (7), 199 (46, [C11H11Fe]+), 187 (10), 121 (29, [C5H5Fe]+), 104 (5), 77 (6),
56 (10, Fe+). HR MS: for C24H28FeN2O calculated 416.1551, foun d 416.1552.
3
(S)-FcCH2N(CH2i-PrOx)(C6H4Me-3) (6c). 1H NMR (CDCl3): 0.86 (d, JHH = 6.8, 3 H, CHMe2),
3
0.93 (d, JHH = 6.7, 3 H, CHMe2), 1.70–1.82 (m , 1 H, CHMe2), 2.29 (s, 3 H, C6H4Me),
Ox
2
3.89–3.97 (m , 2 H, CH2
an d CHOx), 4.05, 4.08 (2 × br d, JHH = 16.8, 1 H, AB system of
CH2Ox); 4.10 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5), 4.17–4.26 (m , 3 H, C5H4 an d
CH2Ox), 4.34, 4.37 (2 × d, JHH = 15.4, 1 H, AB system of FcCH2); 6.50–7.13 (m , 4 H, C6H4).
2
13C NMR (CDCl3): 17.98, 18.74 (CHMe2); 21.90 (C6H4Me), 32.32 (CHMe2), 46.54 (CH2Ox),
50.40 (FcCH2), 67.90 (CH, C5H4), 68.61 (C5H5), 69.13 (CH, C5H4), 70.00 (CH2Ox), 71.93
(CHOx), 84.17 (Cipso, C5H4), 110.60, 114.12, 118.38, 128.87 (CH, C6H4); 138.66 (CMe, C6H4),
148.61 (CN, C6H4), 164.94 (CipsoOx). EI MS, m/z (relative abun dan ce): 430 (9, M• +), 365 (5,
[M – C5H5]+), 306 (4), 305 (21), 304 (39), 303 (100, [1c]• +), 301 (7), 238 (6), 232 (5), 201
(10), 200 (14), 199 (80, [C11H11Fe]+), 196 (5), 121 (38, [C5H5Fe]+), 120 (9), 119 (6), 118 (7),
107 (4), 91 (12), 84 (4), 81 (6), 69 (14), 65 (4), 57 (6), 56 (14, Fe+). HR MS: for C25H30FeN2O
calculated 431.1712, foun d 431.1707.
3
(S)-FcCH2N(CH2i-PrOx)(C6H4Me-4) (6d ). 1H NMR (CDCl3): 0.85 (d, JHH = 6.8, 3 H,
3
CHMe2), 0.93 (d, JHH = 6.7, 3 H, CHMe2), 1.71–7.81 (m , 1 H, CHMe2), 2.23 (s, 3 H,
Ox
C6H4Me), 3.87–3.96 (m , 2 H, CH2
an d CHOx), 4.04 (bs with weak AB satellites, 2 H,
CH2Ox), 4.08 (apparen t t, 2 H, C5H4), 4.15 (s, 5 H, C5H5), 4.13–4.22 (m , 3 H, C5H4 an d
CH2Ox), 4.31, 4.35 (2 × d, JHH = 15.3, 1 H, AB system of FcCH2); 6.72–7.04 (m , 4 H, C6H4).
2
13C NMR (CDCl3): 18.02, 18.78 (CHMe2); 20.28 (C6H4Me), 32.37 (CHMe2), 46.78 (CH2Ox),
50.75 (FcCH2), 67.89 (CH, C5H4), 68.58 (C5H5), 69.18 (CH, C5H4), 70.01 (CH2Ox), 71.95
(CHOx), 84.05 (Cipso, C5H4), 113.89 (CH, C6H4), 126.77 (CMe, C6H4), 129.53 (CH, C6H4),
146.47 (CN, C6H4), 165.00 (CipsoOx). EI MS, m/z (relative abun dan ce): 430 (9, M• +), 365 (4,
[M – C5H5]+), 305 (12), 304 (38), 303 (100, [1d ]• +), 301 (7), 300 (5), 299 (24), 268 (8), 238
(4), 233 (5), 232 (33), 231 (4), 201 (9), 200 (15), 199 (87, [C11H11Fe]+), 197 (6), 186 (9), 159
(8), 146 (4), 139 (4), 127 (5), 122 (4), 121 (49, [C5H5Fe]+), 120 (36), 119 (30), 118 (14), 114
(11), 107 (4), 106 (7), 91 (18), 84 (6), 77 (6), 72 (13), 70 (7), 69 (11), 66 (4), 65 (8), 60 (10),
57 (7), 56 (23, Fe+). HR MS: for C25H30FeN2O calculated 431.1712, foun d 431.1728.
3
(S)-FcCH2N(CH2i-PrOx)(C6H4F-4) (6f). 1H NMR (CDCl3): 0.85 (d, JHH = 6.8, 3 H, CHMe2),
3
Ox
0.92 (d, JHH = 6.8, 3 H, CHMe2), 1.70–1.80 (m , 1 H, CHMe2), 3.88–3.97 (m , 2 H, CH2 an d
CHOx), 3.99, 4.02 (2 × b d, JHH = 16.8, 1 H, AB system of CH2Ox); 4.10 (apparen t t, 2 H,
C5H4), 4.14 (s, 5 H, C5H5), 4.15–4.23 (m , 3 H, CH2
15.1, 1 H, AB system of FcCH2); 6.75–6.94 (m , 4 H, C6H4). 13C NMR (CDCl3): 17.97, 18.71
2
Ox
2
an d C5H4), 4.29, 4.33 (2 × d, JHH =
(CHMe2); 32.33 (CHMe2), 47.10 (CH2Ox), 51.41 (FcCH2), 68.01 (CH, C5H4), 68.61 (CH,
C5H5), 69.20 (CH, C5H4), 70.01 (CH2Ox), 71.95 (CHOx), 83.51 (Cipso, C5H4), 115.25 (d, JFC
=
2
3
4
11.0, CH, C6H4), 115.40 (d, JFC = 4.0, CH, C6H4), 145.19 (d, JFC = 1.8, CN, C6H4), 156.02
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

1228
Štěpnička et al.:
(d, JFC = 237, CF, C6H4), 163.61 (CipsoOx). EI MS, m/z (relative abun dan ce): 434 (10, M• +),
369 (5, [M – C5H5]+), 309 (6), 308 (34), 307 (100), 305 (6), 242 (3), 205 (7), 200 (8), 199 (52,
[C11H11Fe]+), 197 (3), 186 (3), 127 (5), 122 (4), 121 (31, [C5H5Fe]+), 114 (3), 95 (3), 84 (5), 56
(9, Fe+). HR MS: for C24H27FFeN2O calculated 434.1457, foun d 434.1454.
1
3
(S)-FcCH2N(CH2i-PrOx)(C6H4Cl-4) (6g). 1H NMR (CDCl3): 0.86 (d, JHH = 6.7, 3 H, CHMe2),
3
Ox
0.93 (d, JHH = 6.8, 3 H, CHMe2), 1.70–1.80 (m , 1 H, CHMe2), 3.90–3.98 (m , 2 H, CH2 an d
CHOx), 4.05 (bs, 2 H, CH2Ox), 4.11 (apparen t t, 2 H, C5H4), 4.16 (s, 5 H, C5H5), 4.15–4.23
(m , 3 H, CH2
Ox
2
an d C5H4), 4.32, 4.35 (2 × d, JHH = 15.2, 1 H, AB system of FcCH2);
6.72–7.17 (m , 4 H, C6H5). 13C NMR (CDCl3): 17.98, 18.74 (CHMe2); 32.33 (CHMe2), 46.67
(CH2Ox), 50.68 (CH2Fc), 68.06 (CH, C5H4), 68.66 (C5H5), 69.05 (CH, C5H4), 70.10 (CH2Ox),
71.97 (CH2Ox), 83.56 (Cipso, C5H4), 114.59 (CH, C6H4), 122.25 (Cipso, C6H4), 128.90 (CH,
C6H4), 147.10 (Cipso, C6H4), 164.36 (CipsoOx). EI MS, m/z (relative abun dan ce): 450 (6, M• +),
326 (8), 325 (28), 324 (21), 323 (59, [1g]• +), 321 (4), 300 (4), 299 (20), 283 (6), 268 (7), 254
(19), 253 (10), 252 (53), 251 (6), 214 (7), 209 (7), 200 (17), 199 (100, [C11H11Fe]+), 197 (13),
197 (7), 186 (12), 185 (5), 181 (8), 179 (20), 166 (8), 142 (21), 141 (18), 140 (68), 139 (36),
138 (15), 129 (4), 127 (17), 127 (12), 122 (5), 121 (51, [C5H5Fe]+), 114 (29), 113 (5), 111
(12), 105 (5), 84 (14), 78 (5), 77 (11), 75 (8), 72 (15), 70 (15), 69 (20), 66 (6), 65 (6), 60 (9),
57 (6), 56 (28, Fe+). HR MS: for C24H27ClFeN2O calculated 450.1161, foun d 450.1149.
3
(S)-FcCH2N(CH2i-PrOx)(C6H4Br-4) (6h ). 1H NMR (CDCl3): 0.85 (d, JHH = 6.8, 3 H, CHMe2),
3
0.92 (d, JHH = 6.8, 3 H, CHMe2), 1.70–1.80 (m , 1 H, CHMe2), 3.90–9.97 (m , 2 H, CHOx an d
CH2Ox), 4.04 (bs, 2 H, CH2Ox), 4.10 (apparen t t, 2 H, C5H4), 4.15 (s, 5 H, C5H5), 4.15–4.23
2
(m, 3 H, CH2Ox and C5H4), 4.31, 4.34 (2 × d, JHH = 15.4, 1 H, AB system of FcCH2); 4.32 (m, 2 H,
FcCH2), 6.67–7.30 (m , 4 H, C6H4). 13C NMR (CDCl3): 17.99, 18.75 (CHMe2); 32.35 (CHMe2),
46.61 (CH2Ox), 50.60 (FcCH2), 68.07 (CH, C5H4), 68.67 (C5H5), 69.02 (CH, C5H4), 70.11
(CH2Ox), 72.00 (CHOx), 83.55 (Cipso, C5H4), 109.38 (Cipso, C6H4), 115.00 (CH, C6H4), 131.69
(CH, C6H4), 147.50 (Cipso, C6H4), 164.30 (CipsoOx). EI MS, m/z (relative abun dan ce): 496 (6,
M• +), 494 (6), 371 (7), 370 (22), 369 (69, [1h ]• +), 368 (23), 367 (67), 365 (4), 300 (9), 299
(46), 298 (4), 297 (4), 290 (7), 289 (21), 269 (4), 268 (16), 256 (5), 226 (4), 213 (7), 200 (16),
199 (100, [C11H11Fe]+), 197 (6), 197 (7), 187 (6), 186 (18), 185 (5), 184 (6), 148 (4), 129 (4),
127 (11), 122 (6), 121 (68, [C5H5Fe]+), 119 (4), 114 (12), 84 (9), 78 (4), 77 (7), 69 (8), 56 (28,
Fe+). HR MS: for C24H2779BrFeN2O calculated 495.0690, foun d 495.0677.
Addition of Dieth ylzin c to Ben zaldeh yde
A solution of Zn Et2 (1.1 m l 1.1 M in toluen e, 1.2 m m ol) was added to a solution of ligan d
(0.025 m m ol, 2.5 m ole %) an d Ph CHO (1 m m ol) in dry toluen e (2 m l). Th e m ixture was
stirred at room tem perature for 72 h an d th en it was quen ch ed by addin g EtOH (5 m l) an d
1 M HCl. Th e m ixture was extracted with CHCl3 (3 × 5 m l), th e solven t evaporated un der re-
duced pressure an d th e brown residue purified by ch rom atograph y on silicagel colum n usin g
eth yl acetate–h exan e (1:1, v/v) as th e eluen t. Th e purified 1-ph en yleth an -1-ol was im m edi-
ately m ixed with pyridin e an d (1R)-(–)-m en th yl ch loroform ate (m olar ratios 1:1.2:1.3) an d
th e m ixture was stirred overn igh t. En atiom eric purity was th en determ in ed by GC an alysis
of th e resultin g m ixture con tain in g diastereom eric m en th oxycarbon yl esters17. Th e results
are sum m arized in Table I.
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Spaced Ferrocene Oxazolines
1229
Syn th esis of Sch iff Bases 7. Gen eral Procedure
Sch iff bases 7 were obtain ed as given above for 1. Th us, com poun d 7a was obtain ed as a
dark oran ge solid (5.55 g, 92%) from ben zylam in e (2.16 m l, 19.8 m m ol) an d ferrocen e-
carboxaldeh yde (4.24 g, 19.8 m m ol) wh ile com poun d 7b was isolated as a viscous deep oran ge
oil, wh ich crystallized upon stan din g (0.83 g, 52%) from FcCHO (1.070 g, 5.0 m m ol) an d
(R)-1-ph en yleth ylam in e (0.636 m l, 5.0 m m ol).
FcCH=NCH2Ph (7a)18 1H NMR (CDCl3): 4.17 (s, 5 H, C5H5), 4.37 (apparen t t, 2 H, C5H4),
.
4.66 (br s, 2 H, CH2), 4.68 (apparen t t, 2 H, C5H4), 7.22–7.37 (m , 5 H, Ph ), 8.24 (un resolved t,
1 H, CH=N). 13C NMR (CDCl3): 65.13 (CH2), 68.58 (CH, C5H4), 69.06 (C5H5), 70.48 (CH,
C5H4), 80.52 (Cipso, C5H4), 126.87, 127.87, 128.48 (CH, Ph ); 139.64 (Cipso, Ph ), 162.20
(CH=N). EI MS, m/z (relative abun dan ce): 304 (22), 303 (100, M• +), 301 (7), 237 (14, [M –
C5H6]+), 212 (10, [M – Ph CH2]+), 211 (8), 208 (6), 199 (16, [C11H11Fe]+), 186 (7, [FcH]• +), 185
(9), 159 (4), 146 (7), 133 (4), 129 (14), 121 (37, [FeC5H5]+), 91 (18, [C7H7]+), 81 (4), 77(5), 65
(7), 56 (36, Fe+). HR MS: for C18H17FeN calculated 303.0710, foun d 303.0703. For C18H17FeN
(302.4) calculated: 71.31% C, 5.65% H, 4.62% N; foun d: 71.30% C, 5.79% H, 4.57% N.
3
(R)-FcCH=NCH(Me)Ph (7b). 1H NMR (CDCl3): 1.57 (d, JHH = 6.8, 3 H, CHMe), 4.10 (s, 5 H,
3
C5H5), 4.31–4.35 (m , 2 H, C5H4), 4.41 (q, JHH = 6.7, 1 H, CHMe), 4.63, 4.70 (2 × dt, JHH
=
2.5, 1.3, 1 H, C5H4); 7.12–7.40 (m , 5 H, Ph ), 8.19 (s, 1 H, CH=N). 13C NMR (CDCl3): 24.27
(CHMe), 68.28, 68.87 (CH, C5H4 an d CHMe); 68.95 (C5H5), 69.40, 70.31, 70.37 (CH, C5H4
an d CHMe); 80.71 (Cipso, C5H4), 126.53, 126.66, 128.34 (CH, Ph ); 145.33 (Cipso, Ph ), 159.53
(CH=N). EI MS, m/z (relative abun dan ce): 318 (23), 317 (100, M• +), 315 (7), 302 (19, [M –
Me]+), 251 (9, [M – C5H6]+), 212 (11, [M – Ph CH(Me)]+), 211 (9), 199 (11, [C11H11Fe]+), 186
(8), 185 (14, Fc+), 129 (12), 121 (34, [FeC5H5]+), 105 (23, [C8H9]+), 77 (13), 56 (29, Fe+). HR
MS: for C19H19FeN calculated 317.0867, foun d 317.0866.
Syn th esis of Am in es 8. Gen eral Procedure
Am in es 8 were syn th esized as given in detail for 2. Com poun d 7a (2.00 g, 6.6 m m ol) in
m eth an ol (40 m l) was reduced with NaBH4 (1.06 g, 28 m m ol) to give, after isolation as
given above, am in e 8a (1.937 g, 96%) as an oran ge viscous oil. Com poun d 8b was obtain ed
sim ilarly from 7b (0.665 g, 2.10 m m ol) an d NaBH4 (0.328 g, 8.7 m m ol) in m eth an ol (20 m l)
an d isolated as a viscous oran ge oil (0.607 g, 91%).
FcCH2NCH2Ph (8a). 1H NMR (CDCl3): 3.50, 3.79 (2 × s, 2 H, CH2); 4.07 (s, 5 H, C5H5),
4.08, 4.17 (2 × apparen t t, 2 H, C5H4); 7.20–7.34 (m , 5 H, Ph ). 13C NMR (CDCl3): 48.11,
53.26 (CH2); 67.65, 68.25 (CH, C5H4); 68.32 (C5H5), 86.86 (Cipso, C5H4), 126.82, 128.01,
128.32 (CH, Ph ); 140.31 (Cipso, Ph ). IR (Nujol): 3317 (br m ), 3061 (w), 3086 (s), 3026 (m ),
1495 (s), 1357 (m ), 1328 (m ), 1230 (m ), 1105 (vs), 1038 (m ), 1022 (m ), 1001 (s), 819 (vs),
737 (vs), 699 (vs), 582 (m ), 483 (vs). EI MS, m/z (relative abun dan ce): 306 (24), 305 (100,
M• +), 303 (7), 238 (19, [M – C5H5 – 2 H]+), 226 (6), 225 (6), 214 (9), 213 (23), 212 (47, [M –
Ph CH2 – 2 H]+), 200 (37), 199 (25, [C11H11Fe]+), 186 (12, [FcH]• +), 161 (6), 148 (18), 134 (6),
131 (34, [FeC5H5]+), 106(5), 91 (10, [C7H7]+), 78 (5), 65 (6), 56 (31, Fe+). HR MS: for
C
18H19FeN calculated 305.0867, foun d 305.0873.
(R)-FcCH2NHCH(Me)Ph (8b). 1H NMR (CDCl3): 1.33 (d, JHH = 6.6, 3 H, CHMe), 1.57 (br s,
3
2
3
1 H, NH), 3.34, 3.37 (2 × d, JHH = 13.0, 1 H, AB system of CH2); 3.81 (q, JHH = 6.6, 1 H,
CHMe), 4.06 (s, 5 H, C5H5), 4.08 (apparen t t, 2 H, C5H4), 4.13, 4.15 (2 × apparen t q, 1 H,
C5H4); 7.22–7.37 (m , 5 H, Ph ). 13C NMR (CDCl3): 24.59 (CHMe), 46.62 (CHMe), 57.55
(CH2), 67.60, 67.70, 68.09 (CH, C5H4); 68.35 (C5H5), 68.41 (CH, C5H4), 87.18 (Cipso, C5H4),
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

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Štěpnička et al.:
126.67, 126.87, 128.44 (CH, Ph ); 145.65 (Cipso, Ph ). IR (Nujol): 3324 (br m ), 1352 (m ), 1306
(m ), 1123 (m ), 1105 (vs), 1037 (m ), 1023 (m ), 1001 (s), 819 (s), 763 (s), 702 (vs), 588 (m ),
548 (m ), 521 (m ), 483 (vs). EI MS, m/z (relative abun dan ce): 320 (5), 319 (100, M• +), 317
(15), 253 (18, [M – C5H6]• +), 226 (13), 214 (18, [M – Ph CH(Me)]+), 213 (12), 200 (34), 199
(41, [C11H11Fe]+), 186 (14, [FcH]• +), 152 (17), 149 (28), 122 (15), 121 (45, [FeC5H5]+), 105
(12, [C8H9]+), 77 (10, Ph +), 56 (22, Fe+). HR MS: for C19H21FeN calculated 319.1023, foun d
319.1039. [α ]2D0 +50.5 (c 1.0, CHCl3).
Alkylation of 8a with MeI
Am in e 8a (0.100 g, 0.33 m m ol) was dissolved in dry dich lorom eth an e (10 m l), K2CO3 (0.114 g,
0.87 m m ol) was added, an d th e reaction flask was flush ed with argon . Th en , iodom eth an e
(0.103 m l, 1.6 m m ol) was in troduced an d th e m ixture was stirred at room tem perature for
2 days in th e dark. Meth an ol (3 m l) an d water (3 m l) were added, th e yellow organ ic layer
was separated, wash ed with water, an d dried over MgSO4. A subsequen t evaporation fol-
lowed by dryin g un der vacuum (65 Pa, 60 °C, 1 h ) afforded 9 as a yellow m icrocrystallin e
solid in quan titative yield. 1H NMR (CDCl3): 3.05 (s, 6 H, NMe2), 4.30 (s, 5 H, C5H5), 4.35,
4.62 (2 × apparen t t, 2 H, C5H4); 4.98, 5.10 (2 × s, 2 H, CH2); 7.71–7.69 (m , 5 H, Ph ). 13C NMR
(CDCl3): 48.25 (NMe2), 65.83, 66.64 (CH2); 69.67 (C5H5); 70.71 (CH, C5H4), 72.14 (Cipso
,
C5H4), 72.47 (CH, C5H4). For C20H24FeIN (460.4) calculated: 52.09% C, 5.25% H, 3.04% N;
foun d: 51.78% C, 5.40% H, 2.74% N.
Syn th esis of Oxazolin e 10
Oxazolin e 10 was obtain ed as given above for com poun ds 5 an d 6 by stirrin g a m ixture of
7b (1 m m ol), 4b (2 m m ol) an d K2CO3 at 90 °C (bath tem perature) un der argon in th e dark
for 2.5 days. Th e crude m aterial was purified by ch rom atograph y (silica gel, CHCl3), an d
th en recrystallized from h ot eth yl acetate to give 10 as an oran ge crystallin e solid (yield n ot
3
3
determ in ed). 1H NMR (CDCl3): 0.94, 1.02 (2 × d, JHH = 6.7, 3 H, CHMe2); 1.38 (d, JHH
=
3
6.5, 3 H, CHMe), 1.81 (octet, JHH = 6.7, 1 H, CHMe2), 3.32 (s, 2 H, CH2Ox), 3.51, 3.65 (2 × d,
2JHH = 14.0, 1 H, AB system of FcCH2); 3.80 (q, JHH = 6.5, 1 H, CHMe), 3.87–3.95 (m , 1 H,
3
CHOx), 3.98 (dd, JHH,1 ≈ JHH,2 ≈ 8.0, 1 H, CH2Ox), 4.01 (s, 5 H, C5H5), 4.09 (br apparen t t, 2 H,
C5H4), 4.17 (br d of apparen t t, 1 H, C5H4), 4.21 (dd, JHH = 8.2, JHH,2 = 9.7, 1 H, CH2Ox),
4.30 (br d of apparen t t, 1 H, C5H4), 7.21–7.42 (m , 5 H). 13C NMR (CDCl3): 18.25, 18.89
(CHMe2); 19.68 (CHMe), 32.55 (CHMe2), 46.40 (CH2Ox), 49.36 (CH2Fc), 59.70 (CHMe),
67.78, 67.84 (CH, C5H4); 68.34 (C5H5), 69.72 (CH2Ox), 69.78, 70.55 (CH, C5H4); 71.86
(CHOx), 83.25 (Cipso, C5H4), 126.85, 127.59, 128.25 (CH, Ph ); 144.83 (Cipso, Ph ), 165.59
(Cipso, Ox). EI MS, m/z (relative abun dan ce): 444 (7, M• +), 379 (3, [M – C5H5]+), 339 (10, [M –
Ph CH(Me)]+), 318 (36), 317 (100, [M – CH2Ox – H]•+, isobaric with [7b]•+), 214 (12, [m/z 317 –
Ph CH(Me)]+), 199 (31, [C11H11Fe]+), 186 (9, [FcH]• +), 160 (5), 121 (39, [FeC5H5]+), 120 (18),
105 (33, [C8H9]+), 91 (8, [C7H7]+), 77 (19, Ph +), 56 (19, Fe+). HR MS: for C26H32FeN2O calcu-
lated 444.1864, foun d 444.1910. [α ]2D0 –17.4 (c 1.0, CHCl3).
X-Ray Crystallograph y
Compound 2b. Crystals suitable for X-ray an alysis were obtain ed by evaporation of a di-
eth yl eth er solution . Diffraction data were collected on an Non ius KappaCCD diffractom eter
equipped with Oxford Cryostream cooler at 150 K usin g graph ite m on och rom atized MoKα
Collect. Czech. Chem. Commun. (Vol. 68) (2003)

Spaced Ferrocene Oxazolines
1231
radiation (λ = 0.71073 Å) an d an alyzed by HKL program package19. Th e cell param eters were
determ in ed by least-squares fittin g from 16 230 partial diffraction s with 1.0 ≤ θ ≤ 26.0°. Th e
ph ase problem was solved by direct m eth ods (SIR92 20). Non -h ydrogen atom s were refin ed
an isotropically by full-m atrix least-squares on F2 (SHELXL97 21). Hydrogen atom s were in -
cluded in calculated position s with fixed C–H bon d len gth s (arom atic 0.93, CH2 0.97, CH3
0.96, an d NH 0.86 Å) an d assign ed Uiso(H) = 1.2 Ueq(X), wh ere X is th e adjacen t C or N.
Compound 2g. Crystals were grown by slow evaporation of a m eth an ol solution . Diffrac-
tion data were collected an d an alyzed as above. Th e cell param eters were determ in ed by
least-squares fittin g from 20 676 partial diffraction s with 1.0 ≤ θ ≤ 27.5°. Th e structure was
solved by direct m eth ods (SIR92). Non -h ydrogen atom s were refin ed an isotropically. All h y-
drogen atom s were iden tified on a differen ce electron den sity m ap an d freely isotropically
refin ed. Th e refin em en t was carried out by full-m atrix least-squares on F2 (SHELXL97).
Compound 9. Sin gle crystals were obtain ed by recrystallization from h ot m eth an ol. Diffrac-
tion data were collected as given above for 2b . Cell param eters were determ in ed by
least-squares fittin g from 16 230 partial diffraction s with 1.0 ≤ θ ≤ 27.9°. Th e ph ase problem
was solved by direct m eth ods (SIR92). Non -h ydrogen atom s were refin ed an isotropically by
full-m atrix least-squares on F2 (SHELXL97). All h ydrogen atom s were iden tified on th e dif-
feren ce electron den sity m aps an d freely refin ed with isotropic th erm al m otion param eters.
Compound 10. Crystals were grown by recrystallization from eth yl acetate. Th e dffraction
data were collected as given for 2b. Th e cell param eters were determ in ed by least-squares
an alysis from 15 821 partial diffraction s with 1.0 ≤ θ ≤ 27.5°. Th e structure was solved by di-
rect m eth ods (SIR92). Non -h ydrogen atom s were refin ed an isotropically. Hydrogen atom s
were in cluded in calculated position s with fixed C–H bon d len gth s (arom atic CH 0.93,
m eth in e 0.98, CH2 0.97, an d CH3 0.96 Å) an d assign ed Uiso(H) = 1.2 Ueq(C). Th e refin em en t
was carried out by full-m atrix least-squares on F2 (SHELXL97).
CCDC-207928 (2b), -207929 (2g), -207930 (9), an d -207931 (10) con tain th e supplem en -
tary crystallograph ic data for th is paper. Th ese data can be obtain ed free of ch arge via
www.ccd c.cam .ac.u k/ co n t s/ ret rievin g.h t m l (o r fro m t h e Cam brid ge Cryst allo grap h ic
Dat a Cen t re, 12, Un io n Ro ad , Cam b rid ge, CB2 1EZ, UK; fax: +44 1223 336033; o r
deposit@ccdc.cam .ac.uk).
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(4-MeC6H4)CH2–N 1.448 Å; N–C–N 113.0°. Original reference: Hess A., Brosch O.,
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Collect. Czech. Chem. Commun. (Vol. 68) (2003)