Rhodium(II)- and copper(I)-catalyzed intramolecular carbon-hydrogen bond insertions with metal carbenoids derived from diazo ketones

Article abstract of DOI:10.1135/cccc19991807

The decomposition of diazo ketones in the presence of Rh(II) and Cu(I) catalysts affords products of C-H bond insertion in high yields. The effect of structural variation on intramolecular and transannular C-H insertions of diazo ketones has been investig

Full text of DOI:10.1135/cccc19991807

Carbon–Hydrogen Bond Insertions
1807
RHODIUM(II)- AND COPPER(I)-CATALYZED INTRAMOLECULAR
CARBON–HYDROGEN BOND INSERTIONS WITH METAL CARBENOIDS
DERIVED FROM DIAZO KETONES
1,
2
Paul MÜLLER * and Esther MAÎTREJEAN
Department of Organic Chemistry, University of Geneva, 30 Quai Ernest Ansermet,
1
CH-1211 Geneva 4, Switzerland; e-mail: paul.muller@chiorg.unige.ch,
2
esther.maitrejean@chiorg.unige.ch
Received Jun e 29, 1999
Accepted Septem ber 16, 1999
Dedicated to Professor Otto Exner on the occasion of his 75th birthday.
Th e decom position of diazo keton es in th e presen ce of Rh (II) an d Cu(I) catalysts affords
products of C–H bon d in sertion in h igh yields. Th e effect of structural variation on
in tram olecular an d tran san n ular C–H in sertion s of diazo keton es h as been in vestigated. Th e
en an tioselectivity of th e in sertion was exam in ed with 15 ch iral catalysts of differen t struc-
tural types. It was low in all cases. Th e poor en an tioselectivity of th e in sertion of diazo ke-
ton es in com parison to th at obtain ed in in sertion s of diazo esters an d diazo am ides is
attributed to two factors: Th e oxocarben es derived from diazo esters an d diazo am ides are
stabilized by reson an ce of th e carbon yl group with th e h eteroatom . Furth erm ore, th e
con form ation al con strain ts wh ich m ust be overcom e in order to reach th e tran sition state
for in tram olecular in sertion are lower in th e case of carben es derived from diazo keton es
th an in th ose from diazo esters an d am ides owin g to th e h igh er rotation al barriers of am ides
an d esters in com parison with th at of keton es. Th is results in an earlier, an d th erefore less
selective tran sition state for in sertion of diazo keton es.
Key w ord s: Carben oids; Carben es; Diazo com poun ds; En an tioselective catalysis; In sertion s;
Rh odium ; Copper; Ch elates.
Th e reaction of diazo com poun ds with tran sition m etal com plexes derived
from Cu(I), Rh (II), Ru(II), etc. affords m etal carben oids, capable of tran sfer-
rin g th eir carben e m oiety to suitable acceptors1. Th e selectivity of th e m etal
carben oid depen ds upon th e substituen t of th e carben e, th e n ature of th e
m etal an d upon th at of its ligan ds2. If th e ligan ds are ch iral, en an tio-
selective carben e tran sfer m ay occur. Th e developm en t of ch iral m etal
com plexes servin g as catalysts for diazo decom position an d, h en ce, en an tio-
selective carben oid reaction s h as m ade spectacular progress over th e last
ten years. Num erous catalyst–carben e com bin ation s are kn own , an d alm ost
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1808
Müller, Maîtrejean:
fully en an tioselective carben e tran sfer reaction s h ave been realized3. Diazo
esters an d diazo am ides are th e m ost suitable precursors for asym m etric
carben e tran sfer. In con trast, th e en an tioselectivity of diazo keton es in typi-
cal carben oid reaction s is usually low. Except for a few isolated exam ples of
in tram olecular cyclopropan ation s4 an d C–H in sertion s5, en an tioselective
carben oid reaction s of diazo keton es h ave by far n ot m et th e spectacular
success en coun tered with diazo esters an d diazo am ides, alth ough diazo ke-
ton es h ave foun d n um erous successful application s in racem ic syn th esis6.
Som e years ago we h ave reported en an tioselective in tram olecular C–H in -
sertion s of diazoacetate esters in th e presen ce of ch iral Rh (II) carbox-
am idate catalysts, such as [Rh 2{(2S)-m epy} ], wh ich proceeded with
4
en an tioselectivities of up to 95% an d better7 wh ile in sertion reaction s of
structurally an alogous diazo keton es were alm ost totally un selective. A sim -
ilar lack of en an tiocon trol in carben oid reaction s of diazo keton es h as been
foun d by oth er auth ors3, but n o satisfactory explan ation h as been pro-
posed, n or h ave catalysts been design ed to overcom e th is deficien cy.
Th e presen t in vestigation deals with in tram olecular carben oid in sertion
of diazo keton es in th e presen ce of ch iral Rh (II) an d Cu(I) catalysts. It was
expected th at, by varyin g th e structures of th e diazo keton es, an d by
screen in g a series of structurally differen t catalysts, som e leads would
em erge, wh ich would con tribute to th e ration al design of m ore selective
ch iral Rh (II) catalysts. Diazo keton es with variable structures were syn th e-
sized such as to allow th e in vestigation of tran san n ular in sertion s with
diazocycloalkan on es, in tram olecular an d tran san n ular in sertion s of
diazocycloalken on en s, an d in tram olecular in sertion s of diazo ketoesters
h avin g alcoh ol m oieties with differen t steric h in dran ce.
EXPERIMENTAL
General. See ref.8
Catalysts. [Rh 2(OAc)4] (1a) an d [Cu(acac)2] (5a) were purch ased from Fluka or from Pres-
sure Ch em ical Co. Pittsburgh . Th e oth er Rh (II) catalysts were syn th esized by ligan d ex-
ch an ge from [Rh 2(OAc)4]: [Rh 2{(S)-m eba}4] (1b ): ref.9; [Rh 2{(–)-m pm t}4] (1c): ref.10
[Rh 2{(S)-(–)-ptpa} ] (1e): ref.11; [Rh 2{(2S)-m epy} ] (2a): ref.12; [Rh 2{(4S)-m ppim } ] (2b): ref.13
;
;
;
4
4
4
[Rh 2{(S)-tbsp} ] (3a): ref.14; [Rh 2{(R)-(–)-bn p} ] (4a): ref.15; [Rh 2{(R)-(–)Me2bn p} ] (4b): ref.16
4
4
4
[Cu-sem icorrin ] (5b ): ref.17
;
[Cu-iPr-pybox] (5c): ref.18
;
[Rh 2{(+)-dm an th }4] (1d ) an d
[Rh 2{(S)-(–)-ptleu} ] (1f): ref.19 an d th e prolin ate catalysts 3b–3d were provided by M. A.
4
McKervey. Abbreviation s of ligan ds: acac, acetylaceton ate; bn h p, bisn aph th ol ph osph ate;
dm an th , octah ydro-1:4,5:8-dim eth an o-9-an th roate; m eba, 2-m eth oxyeth ylben zoate;
Me2bn h p, 3,3’-dim eth ylbisn aph th ol ph osph ate; m epy, m eth yl 2-pyrrolidon ecarboxylate;
m pm t, 2-carboxym eth ylben zoate; m ppim , m eth yl N-(3-ph en ylpropan oyl)im idazolidin on e-
4-carboxylate; n aph -pro, N-n aph th oyl prolin ate; ptle, N-ph taloyl tert-leucin ate; ptpa,
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1809
N-ph th aloyl ph en ylalalin ate; pybox, 2,4-bis-(3-isopropyloxazolin e)pyridin e; tbbz-pro,
N-(4-tert-butylben zoyl) prolin ate; tbsp, N-(4-tert-butylben zen esulfon yl) prolin ate; tipps-pro,
N-(2,4,6-triisopropylben zen esulfon yl) prolin ate.
Syn th esis an d Reaction of Diazocycloalkan on es 8a–8c
Diazocycloheptan-1-one20 (8a) was syn th esized via form ylation of cycloh eptan on e21 (6)
(61%) followed by deform ylatin g diazo tran sfer with TsN3 (ref.22; yield 90%; yellow oil, puri-
fied by ch rom atograph y (silica gel, eth er–petroleum eth er 33 : 67)). 1H NMR (200 MHz,
CDCl3): 1.66–1.77 (m , 6 H); 2.50–2.58 (m , 4 H).
X
R
COOMe
O
O
O
N
Rh
Rh
Rh
Rh
R
1a [Rh2(OAc)4]
methyl
2a [Rh2{(2S)-mepy}4]
X = CH2
2b [Rh2{(4S)-mppim}4]
X = NC(O)(CH2)2Ph
1b [Rh2{(S)-meba}4]
1c [Rh2{(-)-mpmt}4]
1d [Rh2{(+)-dmanth}4]
2-(1S)-methoxyethylphenyl
2-(-)-carboxymenthylphenyl
(+)-1,2,3,4,5,6,7,8-octahydro-
1:4,5:8-dimethano-9-anthryl
(S)-2-phenyl-1-phthalimidoethyl
(S)-2,2-dimethyl-1-phthalimidopropyl
1e [Rh2{(S)-(-)-ptpa}4]
1f [Rh2{(S)-(-)-ptleu}4]
N
R
H
R
O O
P
R
O
O
O
O
Rh
Rh
Rh
Rh
R
3a [Rh2{(S)-tbsp}4]
3b [Rh2{(S)-tipps-pro}4] 2,4,6-triisopropylbenzenesulfonyl
3c [Rh2{(S)-tbbz-pro}4] 4-tert-butylbenzoyl
4-tert-butylbenzenesulfonyl
4a [Rh2{(R)-(-)-bnhp}4]
R = H
4b [Rh2{(R)-(-)-Me2bnhp}4]
R = Me
3d [Rh2{(S)-naph-pro}4] 1-naphthoyl
CN
O
O
N
N
N
N
N
HOMe2C
HOMe2C
CMe2OH
CMe2OH
Cu
N
N
Cu
TfO OTf
CN
5b [Cu-semicorrin]
5c [Cu-pybox]
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1810
Müller, Maîtrejean:
Diazotransfer via trifluoroacetylation23 (Danheiser procedure). To LiHMDS (1 M in h exan e,
7.14 m l, 1.10 equivalen t) in dry THF (18 m l) th e keton e 6 (6.50 m m ol) in THF (12 m l) was
added dropwise at –78 °C durin g 15 m in . After stirrin g at –78 °C durin g 30 m in ,
CF3CO2CH2CF3 (1.04 m l, 7.8 m m ol) was added with a syrin ge at on ce. After 10 m in , th e
tem perature was raised to –40 °C an d kept for 30 m in . Th e m ixture was poured in to 5% HCl
(35 m l) an d Et2O (45 m l). Th e aqueous layer was extracted with Et2O (2 × 30 m l). Th e or-
gan ic layers were wash ed with saturated NaCl (35 m l) an d th en con cen trated un der reduced
pressure. Th e resultin g crude product was im m ediately dissolved in CH3CN (25 m l) un der
argon , an d Et3N (1.35 m l, 9.7 m m ol) an d H2O (0.11 m l, 1.0 equivalen t) were added.
Meth an esulfon yl azide24 (MsN3, 1.17 g, 9.70 m m ol) in CH3CN (20 m l) was added dropwise
with in 20 m in . Th e m ixture was stirred at 25 °C for 2.5 h an d th en con cen trated to 15 m l
un der reduced pressure. It was diluted with Et2O (45 m l), an d wash ed with 10% NaOH (3 ×
30 m l) an d with saturated NaCl. After dryin g (MgSO4), filtration , an d con cen tration , th e
crude product was purified by flash ch rom atograph y.
2-Diazocyclooctanone11 (8b ). Yield 70% via Dan h eiser procedure; purification by
chromatography (silica gel, petroleum ether–ether–NEt3 80 : 20 : 1); yellow oil. IR (CHCl3): 3 053 m,
2 985 s, 2 934 s, 2 087 s, 1 612 s. 1H NMR (200 MHz, CDCl3): 1.57–1.80 (m , 8 H); 2.50–2.65
(m , 4 H). 13C NMR (50 MHz): 24.4 (t); 25.7 (t); 25.8 (t); 28.4 (t); 29.7 (t); 37.8 (t); 127.8 (s);
198.8 (s). MS: 124 (M+), 95 (38), 81 (80), 67 (100), 55 (99).
2-Diazocyclodecanone11 (8c). Yield 27% via Dan h eiser procedure; purification by
ch rom atograph y (silica gel, h exan e–EtOAc 80 : 20); m .p. 54 °C. IR (CH2Cl2): 3 053 m , 2 928 s,
2 082 vs, 1 607 s, 1 357 m . 1H NMR (200 MHz, CDCl3): 1.30–1.90 (m , 12 H); 2.45–2.61 (m , 2 H);
2.63–2.80 (m , 2 H). 13C NMR (100 MHz): 21.4 (t); 22.1 (t); 23.4 (t); 25.6 (t); 25.7 (t); 28.3 (t);
29.6 (t); 37.7 (t); 128.5 (s); 190.1 (s); MS: 152 ( M+), 95 (38), 67 (100), 55 (85).
Diazo Decom position of Diazocycloalkan on es 8. Gen eral Procedure
Th e diazo keton e 8 (1.00 m m ol) in dry CH2Cl2 (10 m l) was added, with a syrin ge pum p
with in 15 h , to th e previously dried (h eat-gun ) catalyst (0.02 m m ol) in CH2Cl2 (5.0 m l) at
25 °C. After th e addition , th e solven t was evaporated un der reduced pressure, an d th e resi-
due was purified by flash ch rom atograph y to afford th e bicyclic keton e 10 (from 8b) or 11
(from 8c). Th e en an tiom eric excess of th e keton es was determ in ed by GC. For results with
various catalysts, see Table I.
cis-Bicyclo[3.3.0]octan-2-one25 (10). Ch rom atograph y on silica gel with h exan e–EtOAc 90 : 10;
ee by GC with Betadex, 90 °C or Lipodex D, 70 °C. IR (CH2Cl2): 3 053 vs, 2 959 m , 2 870 w, 1
728 vs, 1 459 w, 1 261 m . 1H NMR (200 MHz, CDCl3): 1.20–1.70 (m , 4 H); 1.73–1.98 (m , 3 H);
2.10–2.31 (m , 3 H); 2.47–2.65 (m , 1 H); 2.68–2.85 (m , 1 H). 13C NMR (100 MHz): 26.1 (t);
26.3 (t); 29.8 (t); 33.4 (t); 38.0 (t); 41.0 (d); 52 (d); 223.5 (s). MS: 124 (M+), 95 (66), 80 (60),
68 (39), 67 (100), 55 (27).
cis-Bicyclo[5.3.0]decan-2-one26 (11). Ch rom atograph y on silica gel with h exan e–EtOAc 90 : 10;
absen ce of in duction determ in ed from optical rotation ([α]D 0). IR (CH2Cl2): 3 054 vs, 2 932 s,
1 696 vs, 1 421 m . 1H NMR (400 MHz, CDCl3): 1.05–2.05 (m , 12 H); 2.26–2.41 (m , 2 H);
2.46–2.54 (m , 1 H); 3.07–3.16 (m , 1 H). 13C NMR (100 MHz): 24.5 (t); 25.4 (t); 26.2 (t); 27.8 (t);
32.5 (t); 35.2 (t); 40.4 (d); 43.3 (t); 54.7 (d); 213.9 (s). MS: 152 (M+), 123 (22), 111 (100), 95 (94),
67 (98), 55 (50).
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Carbon–Hydrogen Bond Insertions
1811
Syn th esis an d Decom position of 1-Cycloh exyliden e-3-diazopropan -2-on e (15)
Cyclohexylidenepropan-2-one (14). Th is com poun d was syn th esized in 69% yield from
cycloh exan on e (6d ) an d dieth yl (2-oxopropyl)ph osph on ate (13) accordin g to Villeras an d
.
Ram baud27 1H NMR (200 MHz, CDCl3): 1.44–1.73 (m , 6 H); 2.08–2.19 (m , 5 H); 2.71–2.82
(m , 2 H); 5.97 (s, 1 H).
Cyclohexylidene-3-diazopropan-2-one (15). To sodium h exam eth yldisilazan e (4.1 m l, 4.00
m m ol) in dry THF (5.0 m l) was added dropwise at –78 °C, 1-cycloh exyliden epropan -2-on e
(14; 500 m g, 3.62 m m ol) in THF (10 m l) un der n itrogen . After 30 m in of stirrin g at –78 °C
CF3COOCH2CF3 (0.51 m l, 4.3 m m ol) was added at on ce. After 10 m in , th e tem perature was
allowed to rise to 0 °C. Th e m ixture was h ydrolyzed at –20 °C by addition of 1 M HCl (15
m l) an d th en extracted with Et2O (3 × 25 m l). Th e organ ic layer was dried (MgSO4) an d con -
cen trated un der reduced pressure. Th e resultin g oil was dissolved in CH3CN (12 m l) un der
argon . Et3N (0.75 m l, 5.4 m m ol), H2O (0.65 g, 5.4 m m ol) an d MsN3 (0.65 g, 5.43 m m ol)
were added, an d th e m ixture was stirred for 1.0 h . Th e solven t was partially evaporated, an d
th e rem ain in g solution was dissolved in Et2O (25 m l) an d wash ed with saturated NaCl (3 ×
25 m l). Th e organ ic layer was dried (MgSO4) an d evaporated un der reduced pressure an d th e
resultin g oran ge oil was purified by ch rom atograph y (silica gel, petroleum eth er–Et2O 80 : 20)
to afford 15 (360 m g, 2,19 m m ol, 60%). IR (CHCl3): 1 340 s, 1 605 s, 1 642 s, 2 101 vs,
2 935 m . 1H NMR (400 MHz, CDCl3): 1.52–1.74 (m , 6 H); 2.08–2.20 (m , 2 H); 2.79–2.98 (m ,
2 H); 5.17 (s br, 1 H); 5.69 (s br, 1 H). 13C NMR (100 MHz): 26.2 (t); 27.9 (t); 28.8 (t); 30.2 (t);
38.0 (t); 118.8 (d); 161.0 (s); 186.0 (s). MS: 164 (12, M+), 149 (47), 136 (38), 125 (74), 123 (27),
109 (24) 97 (30), 95 (38), 85 (20), 83 (27), 81 (29), 71 (36), 69 (30), 67 (22), 57 (78), 55 (100).
Diazo decomposition of 15. 1,4,5,6,7,7a-Hexahydro-2H-inden-2-one (16). Th e reaction was
carried out as described above with 100 m g of 15 (0.61 m m ol). Th e catalysts were liberated
from th e residual solven t by h eatin g un der reduced pressure prior to use. Th e keton e28 16
was isolated as colorless liquid after flash ch rom atograph y on silica gel with petroleum
eth er–Et2O 50 : 50; ee by GC with Lipodex D colum n , 120 °C, or Betadex 120, 90–150 °C.
For yields an d ee‘s, see Table II. IR (CHCl3): 2 936 m , 1 697 s, 1 619 s, 1 220 s. 1H NMR (400
MHz, CDCl3): 1.13 (qd, J = 12.32, 3.44, 1 H); 1.33–1.57 (m , 2 H); 1.82–1.89 (m , 1 H);
1.95–2.07 (m , 2 H); 2.12–2.30 (m , 2 H); 2.53–2.69 (m , 2 H); 2.79–2.86 (m , 1 H); 5.84 (s br,
1 H). 13C NMR (100 MHz): 25.3 (t); 27.1 (t); 31.0 (t); 35.1 (t); 41.8 (t); 42.4 (t); 126.8 (d);
184.6 (s); 209.0 (s).
Syn th esis an d Decom position of Alkyl 4-Cycloh exyliden e-2-diazo-3-oxobutan oates
24a–24e
Alkyl 4-cyclohexylidene-3-oxobutanoates (19a, 19b). Th e ph osph in e oxides 18a, 18b were
syn th esized from eth yl diph en ylph osph in ite29 an d alkyl 4-brom o-3-oxobutan oate30 an d
were con den sed with cycloh exan on e accordin g to van den Goorbergh 31
.
Methyl 4-cyclohexylidene-3-oxobutanoate (19a). Yield 67%. IR (CHCl3): 1 731 s, 1 682 m ,
1 612 m . 1H NMR (400 MHz, CDCl3): 1.53–1.72 (m , 6 H); 2.17–2.21 (m , 2 H); 2.79–2.85 (m ,
2 H); 3.47 (s, 2 H); 3.74 (s, 3 H); 6.01 (s, 1 H). 13C NMR (100 MHz): 15.3 (q); 26.1 (t); 27.9 (t);
28.8 (t); 30.2 (t); 38.2 (t); 65.9 (t); 119.7 (d); 165.6 (s); 168.1 (s); 192.3 (s).
Ethyl 4-cyclohexylidene-3-oxobutanoate (19b). Yield 32%. 1H NMR (200 MHz, CDCl3): 1.26
(t, J = 7.1, 3 H); 1.50–1.71 (m , 6 H); 2.13–2.21 (m , 2 H); 2.76–2.84 (m , 2 H); 3.43 (s, 2 H);
4.19 (q, J = 7.1, 2 H); 6.00 (s, 1 H).
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Müller, Maîtrejean:
Ester Exch an ge of 18a. 2,4-Dim eth ylpen tan -3-yl an d
Dicycloh exylm eth yl 4-Cycloh exyliden e-3-oxobutan oates 19c an d 19d
Th e m eth yl ester 19a was h eated with th e appropriate alcoh ol in refluxin g toluen e in th e
presen ce of 4-dim eth ylam in opyridin e for 17 an d 48 h , respectively32. After coolin g, th e m ix-
ture was treated with aqueous NH4Cl an d extracted with EtOAc.
2,4-Dimethylpentan-3-yl 4-cyclohexylidene-3-oxobutanoate (19c). Crude 19c was purified by
ch rom atograph y (silica gel, petroleum eth er–Et2O 95 : 5). Yield 75%. 1H NMR (400 MHz,
CDCl3): 0.87 (d, J = 6.9, 6 H); 0.90 (d, J = 6.9, 6 H); 1.53–1.71 (m , 6 H); 1.84–2.00 (m , 4 H);
2.01–2.08 (m , 2 H); 3.50 (s, 2 H); 4.63 (t, J = 6.4, 1 H); 5.60 (s br, 1 H). 13C NMR (100 MHz):
17.2 (q); 19.5 (q); 21.9 (t); 22.7 (t); 25.4 (t); 28.6 (t); 29.4 (d); 47.9 (t); 52.8 (t); 84.0 (d);
127.2 (d); 131.1 (s); 167.3 (s); 201.5 (s).
Dicyclohexylmethyl 4-cyclohexylidene-3-oxobutanoate (19d ). Crude 19d was purified by ch ro-
m atograph y (silica gel, h exan e–EtOAc 20 : 1). Yield 28%. 1H NMR (200 MHz, CDCl3):
0.81–1.35 (m , 12 H); 1.48–1.81 (m , 18 H); 1.87–2.09 (m , 2 H); 3.14 (s, 2 H); 4.65 (t, J = 5.4,
1 H); 5.59 (s br, 1 H).
Alkyl 4-Cycloh exyliden e-2-diazo-3-oxobutan oates 20a–20d
Methyl 4-cyclohexylidene-2-diazo-3-oxobutanoate (20a). Syn th esized via trifluoroacetylation
(Dan h eiser procedure) in 86% yield. IR (CHCl3): 3 019 s, 2 138 s, 1 712 m , 1 638 m , 1 438
m . 1H NMR (400 MHz, CDCl3): 1.54–1.75 (m , 6 H); 2.22–2.30 (m , 2 H); 2.83–2.88 (m , 2 H);
3.84 (s, 3 H); 6.81 (s, 1 H). 13C NMR (100 MHz): 26.2 (t); 28.0 (t); 28.9 (t); 30.8 (t); 38.5 (t);
52.1 (q); 117.7 (d); 161.9 (s); 164.1 (s); 182.4 (s). MS: 222 (21, M+), 162 (58), 135 (23), 134
(92), 133 (30), 123 (89), 107 (24), 106 (56), 105 (45), 95 (31), 94 (24), 93 (22), 92 (42), 91
(96), 81 (30), 79 (71), 78 (58), 77 (38), 67 (52), 65 (27), 59 (27), 55 (100), 53 (57), 51 (27).
HR MS: 222.0995 (C4H14O3N +2; calculated 222.1005).
Ethyl 4-cyclohexylidene-2-diazo-3-oxobutanoate (20b ). Yield 30% (n ot optim ized). IR
(CHCl3): 2 933 s, 2 137 s, 1 709 s, 1 638 m , 1 603 w. 1H NMR (400 MHz, CDCl3): 1.31 (t, J =
7.1; 3 H); 1.50–1.76 (m , 6 H); 2.19–2.29 (m , 2 H); 2.77–2.89 (m , 2 H); 4.27 (q, J = 7.1, 2 H);
6.80 (s, 1 H). 13C NMR (100 MHz): 14.4 (q); 26.3 (t); 28.0 (t); 28.9 (t); 30.8 (t); 38.5 (t); 61.3 (t);
117.9 (d); 161.5 (s);163.9 (s); 182.6 (s). MS: 236 (22, M+), 162 (58), 135 (21), 134 (83), 133
(29), 123 (100), 107 (25), 106 (47), 105 (36), 95 (28), 94 (22), 93 (29), 92 (37), 91 (70), 81
(30), 79 (56), 78 (43), 77 (28), 67 (43), 55 (83), 53 (47).
(2,4-Dimethylpentan-3-yl) 4-cyclohexylidene-2-diazo-3-oxobutanoate (20c). Yield 87% by diazo
tran sfer with MsN3 (procedure of Taber13). IR (CHCl3): 3 020 vs, 2 136 m , 1 708 s, 1 640 m ,
1 293 m . 1H NMR (200 MHz, CDCl3): 0.87 (d, J = 6.7, 6 H); 0.90 (d, J = 6.7, 6 H); 1.45–1.75
(m , 6 H); 1.81–2.05 (m , 6 H); 4.69 (t, J = 6.3, 1 H); 5.52 (s br, 1 H).
Dicyclohexylmethyl 4-cyclohexylidene-2-diazo-3-oxobutanoate (20d ). Yield 89% via diazo trans-
fer13 with MsN3. IR (CHCl3): 2 932 s, 2 135 s, 1 707 s, 1 640 m, 1 448 m. 1H NMR (200 MHz,
CDCl3): 0.85–1.32 (m , 12 H); 1.49–1.81 (m , 18 H); 1.92–2.05 (m , 2 H); 4.73 (t, J = 5.4, 1 H);
5.52 (s br, 1 H).
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Carbon–Hydrogen Bond Insertions
1813
Alkyl 4-Cycloh exyliden e-2-diazo-3-oxobutan oates 20a, 20b, 20e via 23a, 23b, 23e
Alkyl 4-(1-Hydroxycyclohexyl)-3-oxobutanoates 22. General Procedure33
Th e appropriate alkyl acetoacetate (2.70 m m ol) was added dropwise at 0 °C to NaH (2.90
m m ol) in THF (10 m l). Th e m ixture was stirred for 20 m in , an d th e tem perature was allowed
to rise to 20 °C. It was again cooled to 0 °C an d BuLi (2.8 m m ol) was added dropwise, an d
th e m ixture was stirred for 15 m in . To th is solution of alkyl acetoacetate dian ion (21a, 21b,
21e) was added cycloh exan on e (6d ; 3.80 m m ol) in THF (10 m l), an d th e m ixture was stirred
at 0 °C for 30 m in . After stirrin g for 12 h at 20 °C, th e reaction m ixture was decom posed
with aqueous HCl wh ile coolin g. It was extracted (Et2O), dried (MgSO4), an d evaporated un -
der reduced pressure. Th e crude product was purifed by colum n ch rom atograph y.
Methyl 4-(1-hydroxycyclohexyl)-3-oxobutanoate (22a). Yield 66%. Purification on silica gel
with petroleum eth er–eth er 70 : 30. IR (CHCl3): 3 542 br, 3 019 s, 2 861 w, 1 745 s, 1 709 s,
1 653 w, 1 628 w, 1 228 vs. 1H NMR (400 MHz, CDCl3): 1.19–1.73 (m , 10 H); 2.71 (s, 2 H);
3.14 (s br, 1 H); 3.49 (s, 2 H); 3.75 (s, 3 H). 13C NMR (100 MHz): 21.9 (t); 25.6 (t); 37.5 (t);
50.6 (t); 52.4 (t); 52.8 (t); 70.9 (s); 167.3 (s); 204.1 (s). MS: 214 (11, M+), 196 (20), 171 (28),
139 (36), 126 (21), 123 (26), 122 (51), 116 (100), 101 (45), 99 (88), 98 (26), 97 (28), 95 (20),
84 (42), 81 (84), 74 (21), 70 (25), 69 (49), 59 (41), 57 (25), 56 (21), 55 (74). HR MS: 214.1212
(C11H18O+4 ; calculated 214.1205).
Ethyl 4-(1-hydroxycyclohexyl)-3-oxobutanoate (22b ). Yield 28%. Purification on silica gel
with petroleum eth er–eth er 70 : 30. IR (CHCl3): 3 531 br, 2 921 s, 1 736 s, 1 703 s, 1 650 m .
1H NMR (200 MHz, CDCl3): 1.11–1.18 (m , 10 H); 1.29 (t, J = 7.2, 3 H); 2.69 (s, 2 H); 3.21
(s br, 1 H); 3.45 (s, 2 H); 4.18 (q, J = 7.2, 2 H). 13C NMR (100 MHz): 14.1 (q); 21.9 (t); 25.6 (t);
37.6 (t); 50.9 (t); 52.8 (t); 61.5 (t); 70.9 (s); 166.9 (s); 204.2 (s). MS: 228 (11, M+), 210 (20),
185 (27), 139 (44), 130 (100), 126 (28), 123 (36), 122 (55), 115 (31), 99 (83), 98 (32), 97
(42), 95 (24), 88 (33), 85 (36), 84 (68), 81 (94), 71 (24), 70 (31), 69 (58), 57 (69), 56 (31), 55
(43), 55 (81).
(–)-Menthyl 4-(1-hydroxycyclohexyl)-3-oxobutanoate (22e). Yield 64% from (–)-m en th yl
3-oxobutan oate34. Purification on silica gel with petroleum eth er–eth er 95 : 5. 1H NMR (400
MHz, CDCl3): 0.77 (d, J = 6.9, 3 H); 0.90 (d, J = 7.4, 3 H); 0.92 (d, J = 6.9, 3 H); 0.95–1.73
(m , 17 H); 1.81–1.92 (m , 1 H); 1.98–2.06 (m , 1 H); 2.71 (s, 2 H); 3.24 (s br, 1 H); 3.45 (s,
2 H); 4.70 (m , 1 H). 13C NMR (100 MHz): 16.2 (q); 20.7 (q); 21.9 (t); 22.0 (q); 23.3 (t); 25.6 (t);
26.2 (d); 31.4 (d); 34.1 (t); 37.5 (t); 40.7 (t); 46.9 (d); 51.2 (t); 52.8 (t); 70.8 (s); 75.7 (d);
166.5 (s); 204.4 (s).
Alkyl 4-(1-Hydroxycyclohexyl)-2-diazo-3-oxobutanoates 23
Th e diazo tran sfer was effected accordin g to th e gen eral procedure of Taber32
.
Methyl 4-(1-hydroxycyclohexyl)-2-diazo-3-oxobutanoate (23a). Yield 89%. IR (CHCl3): 3 520 br,
2 936 s, 2 139 s, 1 717 s, 1 638 m . 1H NMR (400 MHz, CDCl3): 1.34–1.55 (m , 6 H);
1.56–1.72 (m , 4 H); 3.03 (s, 2 H); 3.45 (m , 1 H); 3.82 (s, 3 H). 13C NMR (100 MHz): 21.9 (t);
25.6 (t); 37.8 (t); 49.2 (t); 52.2 (q); 71.5 (s); 161.9 (s); 192.9 (s). MS: 240 (3, M+), 169 (52),
142 (34), 137 (27), 123 (20), 109 (20), 99 (32), 97 (32), 95 (24), 81 (69), 55 (100), 54 (44), 53
(20). HR MS: 240.1107 (C11H16O4N +2; calculated 240.1110).
Ethyl 4-(1-hydroxycyclohexyl)-2-diazo-3-oxobutanoate (23b ). Yield 68%; yellow oil. IR
(CHCl3): 3 520 br, 2 936 s, 2 140 s, 1 713 s, 1 637 m . 1H NMR (400 MHz, CDCl3): 1.31 (t, J =
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1814
Müller, Maîtrejean:
7.2, 3 H); 1.58–1.72 (m , 4 H); 3.03 (s, 2 H); 3.50 (m , 1 H); 4.28 (q, J = 7.2, 2 H). 13C NMR
(100 MHz): 14.2 (q); 22.0 (t); 25.7 (t); 37.9 (t); 49.3 (t); 61.6 (t); 71.5 (s); 161.6 (s); 193.1 (s).
MS: 254 (6, M+), 183 (47), 156 (34), 137 (41), 123 (29), 99 (49), 97 (42), 95 (37), 81 (100), 71
(20), 69 (25), 67 (26), 57 (24), 55 (86), 54 (54), 53 (23), 45 (24).
(–)-Menthyl 4-(1-hydroxycyclohexyl)-2-diazo-3-propanoate (23e). Yield 98%; pale yellow oil.
IR (CHCl3): 3 510 br, 2 932 s, 2 139 s, 1 705 s, 1 635 m , 1 456 w. 1H NMR (400 MHz,
CDCl3): 0.80 (d, J = 6.9, 3 H); 0.91 (d, J = 7, 4, 3 H); 0.93 (d, J = 6.9, 3 H); 1.01–1.77 (m , 17 H);
1.78–1.92 (m , 1 H); 2.03–2.11 (m , 1 H); 3.06 (AB, na = 3.075, nb = 3.047, J = 15.8, 2 H); 3.63
(s, br, 1 H); 4.82 (td, J = 10.8, 4.4, 1 H). 13C NMR (100 MHz): 16.5 (q); 20.7 (q); 21.9 (q);
22.0 (t); 23.6 (t); 25.7 (t); 26.6 (q); 31.5 (d); 34.1 (t); 37.9 (t); 41.1 (t); 47.0 (d); 49.3 (t); 71.5 (s);
76.2 (d); 77.6 (s); 161.3 (s); 193.3 (s).
Alkyl 4-Cyclohexylidene-2-diazo-3-oxobutanoates 20a, 20b, 20e via
Dehydration of 23a, 23b, 23e. General Procedure35
To th e diazo com poun d 23 (1.50 m m ol) in pyridin e (10 m l), POCl3 (0.50 m l, 5.5 m m ol) was
added at 0 °C un der argon . After 6 h of stirrin g at 0 °C, th e m ixture was stirred durin g 12 h
at 20 °C. It was poured on ice/water (50 m l) an d extracted with h exan e. Th e organ ic layer
was dried (MgSO4) an d evaporated un der reduced pressure. Th e crude product was purified
by colum n ch rom atograph y (silica gel, petroleum eth er–eth er 95 : 5). Yield: 20a 50%; 20b
68%; yellow oils. For data of 20a–20d see above.
(–)-Menthyl 4-cyclohexylidene-2-diazo-3-oxobutanoate (20e). Yield 66%. IR (CHCl3): 2 930 s,
2 136 s, 1 704 s, 1 640 s. 1H NMR (400 MHz, CDCl3): 0.80 (d, J = 6.9, 3 H); 0.85–0.99 (m ,
6 H); 1.00–1.78 (m , 17 H); 1.81–1.92 (m , 1 H); 1.96–2.12 (m , 1 H); 4.76–4.88 (m , 1 H); 5.56
(s, 1 H). 13C NMR (100 MHz): 16.5 (q); 20.7 (q); 22.0 (q); 22.1 (t); 23.6 (t); 25.4 (t); 26.6 (d);
28.8 (t); 31.5 (d); 34.1 (t); 38.5 (t); 41.2 (t); 47.0 (d); 75.7 (d); 125.7 (d); 131.6 (s); 161.2 (s);
191.0 (s). MS: 346 (1, M+), 208 (28), 163 (21), 162 (46), 138 (25), 134 (21), 95 (49), 83 (100),
81 (29), 69 (46), 57 (32), 55 (57).
Decom position of Diazo Ketoesters 20a–20e. Alkyl 2-Oxo-1,4,5,6,7,7a-h exah ydro-
2H-in den e-1-carboxylates 24a–24e. Gen eral Procedure
For procedure see above: diazo decom position of diazocycloalkan on es 8. For results with
various catalysts, see Table III.
Methyl 2-oxo-1,4,5,6,7,7a-hexahydro-2H-indene-1-carboxylate (24a ). Yield 50–75%. IR
(CHCl3): 2 936 m , 1 710 s, 1 623 w, 1 364 m . 1H NMR (200 MHz, CDCl3): 1.07–1.68 (m ,
3 H); 1.80–2.09 (m , 2 H); 2.16–2.42 (m , 2 H); 2.78–2.90 (m , 2 H); 2.98–3.11 (m , 2 H); 3.75
(s, 3 H); 5.80 (s, 1 H). 13C NMR (100 MHz): 24.9 (t); 26.5 (t); 30.8 (t); 34.0 (t), 45.8 (d); 52 5
(q); 59 1 (d); 124.9 (d); 169.5 (s); 184.2 (s); 201.1 (s).
Ethyl 2-oxo-1,4,5,6,7,7a-hexahydro-2H-indene-1-carboxylate36 (24b ). 1H NMR (400 MHz,
CDCl3): 1.26–1.68 (m , 7 H); 1.84–1.95 (m , 1 H); 1.96–2.11 (m , 1 H); 2.21–2.39 (m , 2 H);
2.81–2.93 (m , 1 H); 2.96–3.05 (m , 2 H); 4.15–4.31 (q, J = 7.3, 2 H); 5.82 (s, 1 H). 13C NMR
(100 MHz): 14.4 (q); 25.3 (t); 26.8 (t); 31.1 (t); 34.3 (t); 46.1 (d); 59.6 (d); 61.8 (t); 125.2 (d);
169.4 (s); 184.3 (s); 201.5 (s).
(2,4-Dimethylpentan-3-yl) 2-oxo-1,4,5,6,7,7a-hexahydro-2H-indene-1-carboxylate (24c). Yield
10–20%. IR (CHCl3): 2 939 m , 1 724 s, 1 701 s, 1 623 s, 1 464 w. 1H NMR (400 MHz, CDCl3):
0.83–0.96 (m , 12 H); 1.15–1.63 (m , 3 H); 1.84–1.98 (m , 3 H); 2.00–2.07 (m , 1 H); 2.21–2.37
(m , 2 H); 2.81–2.88 (m , 1 H); 3.01–3.09 (m , 2 H); 4.60 (t, J = 6.2, 1 H); 5.82 (s, 1 H).
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Carbon–Hydrogen Bond Insertions
1815
13C NMR (100 MHz): 17.1 (q); 17.3 (q); 19.5 (q); 25.1 (t); 25.1 (t); 26.6 (t); 29.4 (d); 30.8 (t);
34.0 (t); 46.3 (d); 59.7 (d); 83.9 (d); 125.2 (d); 183.5 (s); 201.3 (s).
Dicyclohexylmethyl 2-oxo-1,4,5,6,7,7a-hexahydro-2H-indene-1-carboxylate (24d ). Yield
15–79%. 1H NMR (400 MHz, CDCl3): 0.71–2.08 (m , 27 H); 2.17–2.39 (m , 2 H); 2.80–2.87 (m ,
1 H); 2.98–3.03 (m , 2 H); 4.68 (t, J = 5.8, 1 H); 5.82 (s, 1 H). 13C NMR (100 MHz): 25.1 (t);
26.0 (t); 26.1 (t); 26.2 (t); 26.3 (t); 26.4 (t); 26.6 (t); 27.2 (t); 27.6 (t); 29.80 (t); 20.82 (t); 30.9 (t);
34.1 (t); 38.3 (d); 38.4 (d); 46.2 (d); 59.6 (d); 82.7 (d); 125.1 (d); 169.2 (s); 183.6 (s); 201.3 (s).
(–)-Menthyl 2-oxo-1,4,5,6,7,7a-hexahydro-2H-indene-1-carboxylate (24e). Yield 0–50%. 1H
NMR (400 MHz, CDCl3): 0.76 (d, J = 6.9, 3 H); 0.79–1.72 (m , 16 H); 1.80–2.14 (m , 4 H);
2.21–2.38 (m , 2 H); 2.81–2.89 (m , 1 H); 2.96–3.06 (m , 2 H); 4.68–4.77 (m , 1 H); 5.80 (s br,
1 H). 13C NMR (100 MHz): 16.2 (q); 20.7 (q); 21.9 (q); 23.4 (t); 25.1 (t); 25.8 (d); 26.6 (t);
30.9 (t); 31.5 (d); 34.0 (t); 34.2 (t); 40.8 (t); 46.0 (d); 46.9 (d); 59.6 (d); 75.5 (d); 125.0 (d);
168.8 (s); 183.6 (s); 201.2 (s).
Syn th esis an d Decom position of 8-Diazocyclooct-2-en -1-on e37 (26)
Diazocyclooct-2-en-1-one (26)
Cyclooct-2-en -1-on e38 (25) was con verted in 62% yield to 26 by th e gen eral procedure of
Dan h eiser (see above). IR (CHCl3): 3 016 s, 2 934 m , 2 085 s, 1 636 w, 1 578 m . 1H NMR
(200 MHz, CDCl3): 1.68–1.80 (m , 4 H); 2.26–2.36 (m , 2 H); 2.55–2.62 (m , 2 H); 2.55–2.62
(m , 2 H); 5.76–5.84 (dt, J = 12.4, 1.5, 1 H); 6.07–6.20 (dt, J = 12.5, 6.3, 1 H). 13C NMR (100 MHz):
22.5 (t); 23.9 (t); 28.2 (t); 29.7 (t); 126.7 (d); 139.4 (d); 190.5 (s).
Diazo Decomposition of 26.
cis-Bicyclo[3.3.0]oct-3-en-2-one (4,5,6,6a-Tetrahydropentalen-3(3aH)-one (27))
Th e reaction s were carried out un der th e con dition s described above: see diazo decom posi-
tion of diazocycloalkan on es 8. For results, see Table IV. Th e ee was determ in ed by GC with
Lipodex E colum n, 90 °C. Data of 27: IR (CHCl3): 3 013 m , 2 958 m , 2 870 w, 1 700 s, 1 584 m ,
1 450 w, 1 348 m , 1 219 m . 1H NMR (400 MHz, CDCl3): 1.19–1.33 (m , 1 H); 1.57–1.77 (m , 4 H);
1.87–1.94 (m , 1 H); 2.66–2.73 (m , 1 H); 3.32–3.39 (m , 1 H); 6.14 (dd, J = 5.3, 1.8, 1 H); 7.53
(dd, J = 5.5, 3.1, 1 H);. 13C NMR (100 MHz): 23.5 (t); 29.3 (t); 30.1 (t); 46.6 (d); 49.6 (d); 134.5 (d);
167.4 (d); 213.5 (s).
RESULTS AND DISCUSSION
Transannular Insertion of 2-Diazocycloalkan-1-ones 8
Th e 2-diazocycloalkan -1-on es 8a–8c were prepared from th e correspon din g
keton es 6 eith er via form ylation followed by deform ylatin g diazo tran sfer
with tosyl azide (TsN3) in th e presen ce of Et3N, as described20–22 or via tri-
fluoroacetylation an d subsequen t diazo tran sfer with MsN3 (Sch em e 1),
with out isolation of th e in term ediates 7 (m eth od of Dan h eiser23). Th e
Dan h eiser procedure was superior.
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1816
Müller, Maîtrejean:
Th e decom position of 2-diazocycloh eptan -1-on e (8a) with [Rh 2(OAc)4] or
[Cu(acac)2] afforded an un tractable m ixture of products in wh ich cyclo-
h ept-2-en -1-on e (9a) could be detected spectroscopically. In con trast, th e
h igh er h om ologue, 2-diazocyclooctan -1-on e (8b) reacted with [Rh 2(OAc)4]
alm ost quan titatively via tran san n ular in sertion to cis-bicyclo[3.3.0]octan -
2-on e (10) (Table I). Oth er Rh (II) catalysts exh ibited sim ilar selectivity for
tran san n ular C–H in sertion , an d th e poten tially com petitive 1,2-h ydrogen
m igration leadin g to 9b was n ot observed with 8b. Even Cu catalysts,
wh ich are n ot particularly pron e to prom ote C–H in sertion s, provided th e
bicyclic keton e 10 in appreciable yields. Th e Cu(I) catalysts were, h owever,
n ot sufficien tly reactive an d som e un reacted diazoketon e 8b was recovered.
Decom position of 8c with Cu(I) an d Rh (II) catalysts afforded cis-bicyclo-
[5.3.0]decan -2-on e (11) in h igh yield, rath er th an th e expected bicyclo-
[4.4.0]decan -2-on e (12) wh ich is reportedly form ed upon decom position of
8c with CuO. Note th at in th e Cu(II)-catalyzed diazo decom position s, th e
catalytically acive species is a Cu(I) com poun d wh ich is form ed by reduc-
tion of Cu(II) by th e diazo com poun d.
F3C
O
N2
O
O
O
O
(i)
(ii)
(iii)
( )n
( )n
7a - 7c
( )n
( )n
6a - 6c
8a - 8c
9a - 9c
n = 3
n = 5
O
O
O
a : n = 2
b : n = 3
c : n = 5
10
11
1
(i) LiHMDS (1.1 eq.), CF3CO2CH2CF3 (1.2 eq.), -78 oC; (ii) Et3N (1.5 eq.), H2O (1 eq.),
MsN3 (1.5 eq.), 25 oC; (iii) Rh(II), 5%, 25 oC
SCHEME 1
Th e decom position of 2-diazocycloalkan -1-on es can proceed eith er via
1,2-h ydrogen m igration to cycloalken on es or via tran san n ular C–H in ser-
tion . In free carben es, 1,2-h ydrogen m igration is a very fast process with ac-
tivation en ergies in th e ran ge of ca 5 kcal/m ol (ref.39). With m etal
carben oids, h owever, th e selectivity is differen t, an d cyclopropan ation s as
well as in tram olecular C–H in sertion s can be com petitive with h ydrogen
m igration . In tram olecular in sertion s occurrin g in preferen ce over h ydrogen
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1817
m igration from an adjacen t CH3 group of m etal carben oids h ave been
reported40. Olefin form ation becom es predom in an t if th e adjacen t group is
CH2 (ref.41). In our series of diazo keton es h ydrogen m igration predom in ates
with diazocycloheptanone (8a), presum ably owing to the strain in the puta-
tive transannular insertion product (bicyclo[3.2.0]heptan-2-one), but is virtu-
ally absent with 8b and 8c. The still higher diazocycloalkanones were not
investigated owing to their known tendency to suffer hydrogen m igration.
Th e m etal-catalyzed decom position of 2-diazocycloalkan -1-on es 8 h as
been in vestigated in th e past20. Cycloalken on es 9 were form ed with Ag2O,
in stead of rin g-con tracted products derived from th e expected Wolff rear-
ran gem en t. Decom position with CuO, in turn , resulted in m ixtures of prod-
ucts of tran san n ular in sertion togeth er with cycloalken on es. Th us
2-diazocyclodecan -1-on e (8c) afforded cis-bicyclo[4.4.0]decan -2-on e (12;
13%) an d cyclodec-2-en -1-on e (9c; 39%) upon exposure to CuO.
TABLE I
Tran san n ular in sertion of 2-diazocycloalkan -1-on esa
6
Com -
poun d
Catalyst
Solven t
Product
Yield, %
ee, %
8b
8b
8b
8b
8b
8b
8b
8b
8c
8c
8c
8c
8c
8c
[Rh 2(OAc)4] (1a)
CH2Cl2
CH2Cl2
CH2Cl2
pen tan e
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
CH2Cl2
DCEd
10
10
10
10
10
10
10
10
11
11
11
11
11
11
96
86
71
40
90
60
50b
37c
56
83
82
60
50
30
–
12
0
[Rh 2{(S)-m eba} ] (1b)
4
[Rh 2{(5S)-m epy} ] (2a)
4
[Rh 2{(5S)-m epy} ] (2a)
10
9
4
[Rh 2{(4R)-m ppim } ] (2b)
4
[Rh 2{(R)-(–)-bn p} ] (4a)
9
4
[Cu-sem icorrin e] (5b)
[Cu{(R)-isoPr-pybox}] (5c)
[Cu(acac)2] (5a)
7
19
–
[Rh 2(OAc)4] (1a)
–
[Rh 2{(2S)-m epy} ] (1a)
0
4
[Rh 2{(4R)-m ppim } ] (2b)
0
4
[Rh 2{(R)-(–)-bn p} ] (3a)
0
4
[Cu-sem icorrin e] (4b)
0
a
Con dition s: Syrin ge pum p addition of 8 (1.00 m m ol) in CH2Cl2 to th e catalyst (0.02 m m ol)
b
c
in CH2Cl2 at room tem perature (23 °C). Determ in ed by GC, Lipodex E colum n . Un reacted
diazo keton e recovered. DCE, dich loroeth an e, 80 °C.
d
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1818
Müller, Maîtrejean:
Diazo decom position by several ch iral Rh (II) catalysts, wh ich h ave sh own
exception al en an tioselectivity in CH in sertion s of diazo esters, afforded sat-
isfactory yields of 10, but were disappoin tin g with respect to en an tio-
selectivity with ee’s aroun d 10%. Th e ch iral Cu(I) catalysts 5b an d 5c
produced en an tioselectivities of 7 an d 19%, respectively. In addition to th e
catalysts m en tion ed in Table I, several oth er Rh (II) prolin ates an d som e of
th e Cu(I)–Sch iff base com plexes of O’Con n ar42 were also exam in ed, but n o
sign ifican t im provem en t could be ach ieved. A selection of ch iral Rh (II) an d
Cu(I) catalysts was also tested with 8c. However, th ese reaction s proceeded
with out en an tioselectivity.
Intramolecular Insertion of 1-Cyclohexylidene-3-diazopropan-2-one (15)
and 4-Cyclohexylidene-2-diazo-3-oxobutanoates 23a–23e
1-Cycloh exyliden epropan -2-on e (14) was syn th esized from cycloh exan on e
(6d ) an d dieth yl (2-oxopropyl)ph osph on ate (13) in th e presen ce of K2CO3,
an d tran sform ed to th e diazo keton e 15 by th e procedure of Dan h eiser23
.
Reaction of 15 with [Rh 2(OAc)4] un der th e usual con dition s furn ish ed th e
cyclized product 1,4,5,6,7,7a-h exah ydro-2H-in den -2-on e (16) in 60% yield.
Th is yield is in th e ran ge expected for in tram olecular in sertion s of diazo ke-
ton es in to allylic C–H bon ds43 an d com pares favorably with th at reported
for cyclization of th e isom eric diazo keton e 17 to 16 with [Rh 2(OAc)4]
(26%) an d [Cu(OTf)2] (59%, ref.44) or with BF3·Et2O (50%, ref.45). Th e yields
decreased sligh tly with th e asym m etric catalysts. Asym m etric in duction was
very m odest with all of th e catalysts in vestigated. Th e h igh est en an tio-
selecitivty (18%) resulted upon exposure of 15 to [Rh 2{(R)-(–)-bn p} ] (4a).
4
O
O
13
(EtO)2P
O
O
O
N2
(i),(ii)
6d
14
15
(iii)
O
O
N2
(iv)
16
17
(i) NaHMDS (1.1 eq.), CF3CO2CH2CF3 (1.2 eq.), -78 oC; (ii) Et3N (1.5 eq.), H2O (1 eq.),
MsN3 (1.5 eq.), 25 oC; (iii) Rh(II), 5%, 25 oC; (iv) [Rh2(OAc)4] or [Cu(OTf)2] or BF3Et2O
SCHEME 2
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1819
Th e un saturated diazo ketoesters 20a, 20b were syn th esized by con den sa-
tion of cycloh exan on e with th e ph osph in e oxides29 18a, 18b to afford th e
un saturated esters 19a, 19b in 67 an d 32% yields, respectively31. Th e
2,4-dim eth ylpen tan -3-yl an d dicycloh exylm eth yl esters 19c, 19d , in turn ,
were syn th esized via ester exch an ge of 19a with th e respective alcoh ols in
th e presen ce of DMAP in refluxin g toluen e32. Diazo tran sfer accordin g to
Danheiser23 proceeded in 80–90% yield to the diazo ketoester 20. Alterna-
tively, diazo esters 20 were accessible via condensation of cyclohexanone (6d)
with alkyl dilithioacetoacetate (21). Since dehydration of the interm ediate alco-
hol 22 to 19 could not be achieved33,46, the sequence of steps was inverted, i.e.,
diazo transfer was effected prior to dehydration. Diazo transfer with 22 was carried
out according to Taber47, and dehydration of the diazo alcohol 23 proceeded
smoothly to 20 under the conditions reported by Padwa (POCl3/pyridine)48. This ap-
proach was used for the preparation of 20a, 20b, and 20e.
Th e in tram olecular in sertion of th e m eth yl an d eth yl esters 20a, 20b pro-
ceeded in 80–85% yield to th e kn own h exah ydro-2H-in den e derivative 24a,
24b (cis-isom er). Th e yields with th e sterically m ore crowded esters sign ifi-
can tly decreased to 30–50%. Th ese reaction s were accom pan ied by products
of carben oid in sertion s in to th e C–H bon ds of th e alcoh ol m oiety, a
well-kn own ph en om en on in reaction s of m en th yl diazoacetates49. Owin g
to th eir in sufficien t activity, th e ch iral Rh (II) carboxam idate catalysts were
n ot gen erally used for diazo decom position in th is series, but were replaced
by catalysts based on optically active carboxylic acids an d bin aph th ol ph os-
ph ates. Yields of th e desired in sertion products were con siderably lower
TABLE II
In tram olecular C–H in sertion a of 1-cycloh exyliden e-3-diazopropan -2-on e (15)
Catalyst
16, yield, %
ee, %
[Rh 2(OAc)4] (1a)
60
40
24
48
36
42
–
3
[Rh 2{(S)-(–)-ptpa} ] (1e)
4
[Rh 2{(2S)-m epy} ] (2a)
5
4
[Rh 2{(S)-tbps} ] (3a)
5
4
[Rh 2{(S)-n aph -pro} ] (3d )
3
4
[Rh 2{(S)-(–)-bn p} ] (4a)
18
4
a
For con dition s, see Table I.
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1820
Müller, Maîtrejean:
th an with [Rh 2(OAc)4] an d en an tioselectivities varied from 0 to 23%. Repre-
sen tative exam ples are sum m arized in Table III.
O
O
O
O
O
O
Ph2P
OR
OR
18a,18b
6d
19a - 19d
OM OM
OR
(iv),(v)
O
O
O
O
O
O
OR
OR
OR
HO
HO
N2
N2
(i)
(ii)
20a - 20e
22a,22b,22e
23a,23b,23e
(iii)
H
a : R = Me
b : R = Et
c : R = CH(isoPr)2
d : R = CH(C6H11 2
)
O
e : R = (-)-menthyl
24a - 24e
COOR
(i) Et3N (2 eq.), MsN3 (1.1 eq.), 25 oC; (ii) Pyridine, POCl3 (4 eq.), 0 oC,
(iii) Rh(II), 5%, 25 oC; (iv) LiHMDS (1.1 eq.), CF3CO2CH2CF3 (1.2 eq.), -78 oC;
(v) Et3N (1.5 eq.), H2O (1 eq.), MsN3 (1.5 eq.), 25 oC
SCHEME 3
Transannular Insertion of 8-Diazocyclooct-2-en-1-one (26)
8-Diazocyclooct-2-en -1-on e (26) was syn th esized by diazo tran sfer with
cycloct-2-en -1-on e (25) accordin g to Dan h eiser23. Exposure of 26 to
[Rh 2(OAc)4] afforded cis-bicyclo[3.3.0]oct-3-en -2-on e (4,5,6,6a-tetrah ydro-
pen talen -3(3aH)-on e) (27) in 60% yield (Table IV). With th e ch iral Rh (II)
carboxam idate catalysts th e yields were som ewh at lower, but n o sign ifican t
level of en an tioselectivity could be ach ieved.
O
O
N2
O
O
(i),(ii)
(iii),(iv)
(v)
6b
26
27
25
(i) Br2 (1 eq.), HOCH2CH2OH (1 eq.). 5-10 oC, MeOH (2 eq.), reflux 72 h; (ii) H2SO4 5%;
(iii) LiHMDS (1.1 eq.), CF3CO2CH2CF3 (1.2 eq.), -78 oC; (iv) Et3N (1.5 eq.), H2O (1 eq.),
MsN3 (1.5 eq.), 25 oC; (v) Rh(II) or Cu(I), 5%, 25 oC
SCHEME 4
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1821
Enantioselectivity in C–H Insertions of Diazo Ketones
Th e absen ce of en an tioselectivity in tran sition m etal-catalyzed decom posi-
tion s of diazo keton es is a well kn own ph en om en on . Doyle h as proposed
an in terpretation for th e in tram olecular cyclopropan ation of diazo esters as
com pared to th at of th e an alogous diazo keton es in th e presen ce of Rh (II)
carboxam idates4c: In th e diazo esters th e carben oid reaction occurs from a
con form ation 28a in wh ich th e carbon yl group of th e m etal-com plexed
carben e poin ts away from th e plan e defin ed by th e ligan ds of th e m etal. In
TABLE III
In tram olecular in sertion a of alkyl 4-cycloh exyliden e-2-diazo-3-oxobutan oates 19a–19e
Com poun d
R
Catalyst
24, yield, %
ee, de, %
20a
20a
20a
20a
20a
20a
20b
20b
20b
20c
20c
20c
20d
20d
20d
20d
20e
20e
20e
20e
Me
Me
Me
Me
Me
Me
Et
[Rh 2(OAc)4] (1a)
85
65
65
81
95
66
80
20
70
40
20
12
31
15
30
32
50
40
30
35
–
13
13
8
[Rh 2{(+)-dm an th } ] (1d )
4
[Rh 2{(S)-tbps} ] (3a)
4
[Rh 2{(S)-tipps-pro} ] (3b)
4
[Rh 2{(S)-tbbz-pro} ] (3c)
7
4
[Rh 2{(R)-Me2bn h p} ] (4b)
12
–
4
[Rh 2(OAc)4] (1a)
Et
[Rh 2{(5S)-m epy} ] (2a)
5
4
Et
[Rh 2{(R)-(–)-bn p} ] (4a)
10
–
4
(isoPr)2CH
(isoPr)2CH
(isoPr)2CH
(C6H11)2CH
(C6H11)2CH
(C6H11)2CH
(C6H11)2CH
(–)-Men th yl
(–)-Men th yl
(–)-Men th yl
(–)-Men th yl
[Rh 2(OAc)4] (1a)
[Rh 2{(S)-(–)-ptpa} ] (1e)
0
4
[Rh 2{(S)-tbps} ] (3a)
2
4
[Rh 2(OAc)4] (1a)
–
[Rh 2(+)-m pm t} ] (1c)
?
4
[Rh 2{(S)-(–)-ptpa} ] (1e)
3
4
[Rh 2{(R)-(–)-bn p} ] (4a)
0
4
[Rh 2(OAc)4] (1a)
–
[Rh 2{(R)-m eba} ] (1b)
16
8
4
[Rh 2{(S)-ptleu} ] (1f)
4
[Rh 2{(S)-tbps} ] (3a)
0
4
a
For con dition s, see Table I.
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1822
Müller, Maîtrejean:
th is con form ation , th e ch ain con tain in g th e double bon d is in close prox-
im ity of th e ch iral ligan ds. In con trast, in th e case of diazo keton es, th e car-
bon yl group of th e product determ in in g con form ation 29b m igh t be
orien ted towards th e plan e of th e ligan ds. In th is con form ation , th e h ydro-
carbon ch ain con tain in g th e reactin g double bon d is turn ed away from th e
ch iral ligan ds, th e in teraction s with th e ligan ds are reduced an d en an tio-
con trol decreases. A sim ilar situation could prevail for in tram olecular in ser-
tion s. However, it is n ot clear wh y carben oids derived from diazo esters
prefer con form ation 28a an d carben oids derived from diazo keton es sh ould
occur preferen tially in con form ation 29b.
Doyle50 an d Hash im oto3d,11 h ave provided m odels for asym m etric in duc-
tion for in tram olecular in sertion s of diazo esters an d diazo am ides with
Rh (II) carboxam idate an d carboxylate catalysts, respectively. Th e X-ray
structures of th eir catalysts exh ibit som e, th ough lim ited structural sim ilari-
ties aroun d th e coordin ation site of th e carben e. In both cases, two adja-
cen t quadran ts are essen tially occupied by th e ch iral ligan ds. In con trast,
th e ch iral Rh (II) bin aph th ol ph osph ate an d ch iral Cu(I) catalysts h ave c2
sym m etry an d, alth ough all of th ese catalysts m ay produce en an tio-
selectivity with diazo esters an d diazo am ides, th ey are un selective with
diazo keton es. Sin ce catalysts as differen t as c2-sym m etric Cu(I)–sem icorrin
com plex 5b, th e Cu(I)–pybox catalyst 5c, th e Rh (II) carboxylates, Rh (II)
carboxam idates, an d Rh (II) bin aph th ol ph osph ates fail with respect to
en an tioselectivity with diazo keton es, it appears th at th is failure m igh t arise
from th e diazo keton es or th e carben es derived th erefrom rath er th an from
th e catalysts. Th e carben es derived from diazo keton es differ from th e ester
an d am ide coun terparts with respect to two properties: reson an ce in terac-
tion s between th e h eteroatom s an d th e carbon yl group in oxycarbon yl
TABLE IV
Tran san n ular in sertion a of 8-diazocyclooct-2-en -1-on e (26)
Catalyst
Solven t, T, °C
27, yield, %
ee, %
[Rh 2(OAc)4] (1a)
CH2Cl2, 23
DCE, 80
60
30
52
55
–
5
[Rh 2{(2S)-m epy} ] (2a)
4
[Rh 2{(4R)-m ppim } ] (2b)
CH2Cl2, 23
CH2Cl2, 23
10
5
4
[Rh 2{(R)-(–)-bn p} ] (4a)
4
a
For con dition s, see Table I.
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1823
carben es an d am ides, respectively, will result in a decrease in positive
ch arge at th e carbon yl group an d, th ereby, ren der th e carben e less elec-
tron -deficien t. Th e selectivity of th e carben e decreases with in creasin g elec-
tron deficien cy. Th e question h as n ot been in vestigated system atically with
diazo keton es, but it is kn own th at th e Ham m ett ρ-value for in tram olecular
ben zylic in sertion of diazo acetoacetates decreases from –1.39 with
[Rh 2(acam )4] (acam = acetam ide) to –1.26 with [Rh 2(OAc)4] an d –0.66 with
[Rh 2(pfb)4] (pfb = perfluorobutyrate)51. Note th at in th e above m en tion ed
lin ear free en ergy relation sh ips, th e electroph ilic n ature of th e carben e was
m odulated by th e electron -attractin g n ature of th e ligan ds of th e catalyst,
an d n ot by th e substituen t of th e carben e. A less electron -with drawin g
ligan d will lead to a later tran sition state an d, h en ce, to h igh er selectivity.
Pirrun g an d Moreh ead h ave related th e selectivity of th e Rh -carben oids
with th e degree of backbon din g from th e m etal to th e vacan t p-orbital of
th e carben e. Backbon din g in creases th e stabilty of th e carben e an d, h en ce,
its selectivity52. Th ese ten den cies sh ould apply in an alogy to diazo keton es
wh ich are expected to produce m ore electroph ilic an d, th erefore, less selec-
tive carben es in com parison with carben es derived from diazo esters or
am ides.
In addition , con form ation al effects m ay be of im portan ce in in tra-
m olecular an d tran san n ular in sertion s. To our kn owledge, n o data are avail-
able for th e preferred con form ation s an d th e rotation al barriers of
oxocarben es, an d th erefore we lim it th e discussion on con sequen ces of th e
in troduction of fun ction alities adjacen t to th e carbon yl group. In acyclic al-
deh ydes an d keton es, th e m ost stable con form ation s h ave very sim ilar en -
ergies an d th e rotation al barriers are sm all, in th e ran ge of 0.7–1.2 kcal/m ol
(ref.53). A double bon d con jugated with th e carbon yl fun ction h as on ly lit-
tle effect on th e con form ation al m obility. Acrolein exists m ain ly in th e
s-trans con form ation wh ich is m ore stable by 1.7 kcal/m ol th an th e s-cis
con form er; th e rotation al barrier is 5.0–6.4 kcal/m ol. Acrylic acid an d
acrylic esters exh ibit sm all en ergy differen ces between th e s-cis an d th e
s-trans con form ation s, an d th e rotation al barriers are below 4 kcal/m ol. Es-
ters occur in two preferred con form ation s, sin ce th e C–O bon d h as a con -
siderable double bon d ch aracter. Th e Z- (or trans) con form er 30 is m ore
stable by 5–6 kcal/m ol th an th e E- (or cis) isom er 31 with a rotation al bar-
rier of 10–13 kcal/m ol. In am ides th e structures are n early plan ar; in
N-m eth ylacetam ide th e Z-con form er is m ore stable th an E by 2.1–2.5
kcal/m ol, an d th e barrier for rotation is 21.3 kcal/m ol. In spection of m olec-
ular m odels sh ows th at in th e case of in tram olecular C–H in sertion s, form a-
tion of a five-m em bered rin g m ay n ot occur from th e Z-isom er 31, th e
Collect. Czech. Chem. Commun. (Vol. 64) (1999)

1824
Müller, Maîtrejean:
reactin g cen ters bein g too far apart. Th e E-con form er 30 is m ore suited; h ow-
ever, in order to allow in teraction between th e carben ic cen tre an d both at-
om s of th e reactin g C–H bon d, wh ich is required to reach th e
th ree-m em bered tran sition state for in sertion , th e con form ation m ost favor-
able for in sertion h as th e O–C bon d of th e alcoh ol ben t out of th e plan e of
th e carbon yl group as depicted in 32. Th is im plies th at th e rotation al barrier
m ust at least partly be overcom e in order to reach th e tran sition state for in -
sertion . Th is results in an in creased en ergy of activation an d, th erefore, in a
later tran sition state an d h igh er selectivity in com parison with th at observed
with diazo keton es. An an alogous argum en t sh ould apply to diazo am ides.
X
O
O
LnM
X
LnM
H
H
H
H
O
O
H
H
H
28a : X = O
28b : X = CH2
29a : X = O
29b : X = CH2
R
H
O
32
O
R
R
H
O
O
cis-(E)- 30
trans-(Z)- 31
SCHEME 5
Reson an ce stabilization of th e carben e an d con form ation al effects are in -
tercon n ected; th e con sequen ces of both effects poin t in to th e sam e direc-
tion , an d th ey are con sisten t with th e experim en tal results presen tly
available. It is clear, h owever, th at th is h ypoth esis sh ould be tested by ex-
perim en tal an d th eoretical m eth ods.
The authors are indebted to Prof. M. A. McKervey for providing samples of the Rh(II) prolinate cata-
lysts. This work was supported by the Swiss National Science Foundation (grants No. 20-45255.95
and No. 20-48156.96) and by the University of Geneva.
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Collect. Czech. Chem. Commun. (Vol. 64) (1999)

Carbon–Hydrogen Bond Insertions
1825
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