Encyclopedia of Reagents for Organic Synthesis || Glyoxylyl Chloride p ...
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GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE 1 Glyoxylyl Chloride p-Toluenesulfonylhy- drazone 1 S N H N Cl O O O [14661-69-9] C 9 H 10 ClN 2 O 3 S (MW 261.73) InChI = 1/C9H9ClN2O3S/c1-7-2-4-8(5-3-7)16(14,15)12-11-6- 9(10)13/h2-6,12H,1H3 InChIKey = HQXCAVDYGRHYMF-UHFFFAOYAK (synthesis of α-diazo esters and amides 2 ) Physical Data: mp 103–110 ◦ C (dec). Solubility: sol methylene chloride, chloroform, THF, and warm benzene. Preparative Method: not commercially available; however, it can be prepared readily by the reaction of p-Toluenesulfonylhydra- zide and Glyoxylic Acid. 2 Handling, Storage, and Precaution: anhydrous conditions are required; it is advisable to prepare the reagent freshly prior to use. Original Commentary Ioannis Grapsas & Shahriar Mobashery Wayne State University, Detroit, MI, USA Introduction. Glyoxylyl chloride p-toluenesulfonylhydra- zone (1) is a versatile reagent for the synthesis of diazoacetyl esters and amides, which upon heating in the presence of a metal catalysts or irradiation generate reactive carbene intermediates. 1 Compound (1) undergoes reaction with alcohols to give the corres- ponding α-diazoacetyl esters under mild basic conditions. Typi- cally, 2 equiv of Triethylamine are used in this reaction (eq 1). However, sulfinate species have been reported to contaminate the product. 1b Corey and Meyers have shown that the formation of this undesired byproduct can be largely circumvented by the use of N,N-dimethylaniline instead of Et 3 N (eq 2). 1b HO N 2 O O (1) Et 3 N (2 equiv) O O Cu 2 O 39% (1) The existing alternative preparative methods for the α-diazo esters, such as diazotization of glycine esters, 3 pyrolysis of N-acyl-N-nitrosoglycine esters, 4 base-catalyzed cleavage of α-diazo-β-ketoacetates, 5 reactions of alkoxycarbonylmethylene- phosphoranes with arenesulfonyl azides, 6 or acid-catalyzed decomposition of acetic esters with aryltriazene substituents, 7 all suffer from the disadvantage of being multistep synthetic proce- dures, and that at times harsh conditions (high temperature, strong acid or base) must be employed. RO H OH RO H O N 2 O RO O (1) PhNMe 2 90% O Cu 2+ 84% H (2) Intramolecular Cyclopropanation. The resultant α-diazo- acetyl ester from the reaction of (1) and an unsaturated alcohol undergoes cyclization in the presence of transition metals to give cyclopropyl derivatives (eq 3, 4); the reaction proceeds via an intermediary carbene species. 1 Owing to the geometric constraints of the intramolecular cyclopropanation, the substituents and the product acquire all-cis configurations. 2 This is in contrast to the bimolecular cyclopropanation, which is unable to achieve stero- chemical control, resulting in mixtures of products. OH O N 2 O O O H (1) PhNMe 2 70% Cu 2+ 88% H (3) R OH (1) PhNMe 2 83–93% R O N 2 O Cu + 75–90% O O H H R (4) C–H and C–C Carbene Insertion Reactions. Intramolecular carbene insertion at an unactivated bridgehead site is reported from an α-diazoacetyl ester precursor (eq 5). 8 O O HO O O O O N 2 O O (1) Et 3 N 73% O O Rh 2 (OAc) 2 45% (5) Decomposition of 6-(α-diazoacetamide)penicillanate in the presence of copper(II) or rhodium(II) in refluxing benzene resulted in the formation of a cycloheptatriene moiety (eq 6). 9
Transcript of Encyclopedia of Reagents for Organic Synthesis || Glyoxylyl Chloride p ...
GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE 1
Glyoxylyl Chloride p-Toluenesulfonylhy-drazone1
SNH
NCl
OOO
[14661-69-9] C9H10ClN2O3S (MW 261.73)InChI = 1/C9H9ClN2O3S/c1-7-2-4-8(5-3-7)16(14,15)12-11-6-
9(10)13/h2-6,12H,1H3InChIKey = HQXCAVDYGRHYMF-UHFFFAOYAK
(synthesis of α-diazo esters and amides2)
Physical Data: mp 103–110 ◦C (dec).Solubility: sol methylene chloride, chloroform, THF, and warm
benzene.Preparative Method: not commercially available; however, it can
be prepared readily by the reaction of p-Toluenesulfonylhydra-zide and Glyoxylic Acid.2
Handling, Storage, and Precaution: anhydrous conditions arerequired; it is advisable to prepare the reagent freshly prior touse.
Original Commentary
Ioannis Grapsas & Shahriar MobasheryWayne State University, Detroit, MI, USA
Introduction. Glyoxylyl chloride p-toluenesulfonylhydra-zone (1) is a versatile reagent for the synthesis of diazoacetylesters and amides, which upon heating in the presence of a metalcatalysts or irradiation generate reactive carbene intermediates.1
Compound (1) undergoes reaction with alcohols to give the corres-ponding α-diazoacetyl esters under mild basic conditions. Typi-cally, 2 equiv of Triethylamine are used in this reaction (eq 1).However, sulfinate species have been reported to contaminate theproduct.1b Corey and Meyers have shown that the formation ofthis undesired byproduct can be largely circumvented by the useof N,N-dimethylaniline instead of Et3N (eq 2).1b
HO N2O
O
(1)
Et3N (2 equiv)
O O
Cu2O
39%
(1)
The existing alternative preparative methods for the α-diazoesters, such as diazotization of glycine esters,3 pyrolysis ofN-acyl-N-nitrosoglycine esters,4 base-catalyzed cleavage ofα-diazo-β-ketoacetates,5 reactions of alkoxycarbonylmethylene-phosphoranes with arenesulfonyl azides,6 or acid-catalyzeddecomposition of acetic esters with aryltriazene substituents,7 allsuffer from the disadvantage of being multistep synthetic proce-dures, and that at times harsh conditions (high temperature, strongacid or base) must be employed.
RO
H
OHRO
H
O
N2O
RO
O
(1)PhNMe2
90%
O
Cu2+
84%
H
(2)
Intramolecular Cyclopropanation. The resultant α-diazo-acetyl ester from the reaction of (1) and an unsaturated alcoholundergoes cyclization in the presence of transition metals to givecyclopropyl derivatives (eq 3, 4); the reaction proceeds via anintermediary carbene species.1 Owing to the geometric constraintsof the intramolecular cyclopropanation, the substituents and theproduct acquire all-cis configurations.2 This is in contrast to thebimolecular cyclopropanation, which is unable to achieve stero-chemical control, resulting in mixtures of products.
OH ON2
O
OO
H(1)PhNMe2
70%
Cu2+
88%H
(3)
R
OH(1)
PhNMe2
83–93% R
ON2
O
Cu+
75–90%O
OH
H
R (4)
C–H and C–C Carbene Insertion Reactions. Intramolecularcarbene insertion at an unactivated bridgehead site is reported froman α-diazoacetyl ester precursor (eq 5).8
O
O
HO
O
O
O
O
N2
O
O
(1)Et3N
73%
OO
Rh2(OAc)2
45%
(5)
Decomposition of 6-(α-diazoacetamide)penicillanate in thepresence of copper(II) or rhodium(II) in refluxing benzeneresulted in the formation of a cycloheptatriene moiety (eq 6).9
2 GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE
N
S
CO2R
H2N
ON
S
CO2R
HN
O
O
N2
N
S
CO2R
HN
O
(1)Et3N
70%
Rh2+
25%
O (6)
Photoaffinity Labels. As an application of the carbeneinsertion reaction in structural studies of macrobiomolecules,radioactively labeled α-diazo esters have been used as photoaffin-ity labels.10 Such esters are designed to bind specific targettedbiological receptors (e.g. enzymes, membrane receptor proteins,nucleic acids, etc.). Photolysis of the complex generates the high-energy carbene species that inserts into C–H or X–H (X = a heteroatom) bonds in the receptor molecule readily at ambient temper-ature. In the absence of a facile insertion reaction, the resultantunquenched carbene may undergo Wolff rearrangement, therebywasting a percentage of the reactive species for photoaffinitylabeling.11 The structures of a number of such biologically ac-tive molecules are shown in (2)–(9); these molecules are preparedtypically by the reaction of reagent (1) with the correspondingalcohols in moderate to good yields.10
O
ON2
(2)
HO
O
ON2
OH
(4)
O
ON2
(3)
ON2
O
NPr2
H
O
O
(6)(5)
ON2
O
ON2
O
ON2
O
(7) (8)
O
ON2
(9)
First Update
Mingyi Liao & Jianbo WangPeking University, Beijing, China
Glyoxylyl chloride p-toluenesulfonylhydrazone (1) continuesto be a powerful reagent for the synthesis of diazoacetyl estersand amides. In most cases, the diazoacetyl esters and amides,which can be obtained from the reaction of (1) with correspondingalcohols or amines, are subjected to the catalysis with transitionmetal complex. A series of synthetically useful transformations,typically cyclopropanation, C–H insertion and ylide formation,can occur in these catalytic reactions. There are several excel-lent reviews in this area that have been published during the pastdecade.12
Intermolecular Cyclopropanation. Transition metal cata-lytic decomposition of diazocarbonyl compounds in the presenceof alkenes provides a facile and powerful means for construct-ing cyclopropanes. Due to the high regio- and stereoselectivities,intramolecular cyclopropanation has received considerable atten-tion during the past several decades.13 Intramolecular cyclopropa-nation has recently mainly focused on enantioselective reactions.Thus, an allylic alcohol reacts with compound (1) to give thecorresponding diazoester. The allylic diazoester is then decom-posed in the presence of a chiral catalyst to afford the cyclo-propyl derivative in high enantiomeric excess. In some casesthe resultant cyclopropyl derivatives were further transformedinto useful molecules such as conformationally restricted peptideisosteres.13a,c–e,h
Intermolecular cyclopropanation of α-diazo carbonyl com-pounds is also reported.14 For example, ethyl glycolate under-goes reaction with compound (1) to give the diazo diester, whichwas subsequently reacted with C60 to form a methanofullerene(eq 7).14
Haddad and Galili have reported a highly diastereoselectivecyclopropanation of alkenes with the Oppolzer’s sultam as chiralauxiliary (eq 8).14b Reaction of (1) with the sultam gives a highyield of the corresponding diazoacetyl amide.
Ylide Reaction. Ylide formation in catalytic carbene transferreactions has attracted considerable attention in the past decade.The ylide can be easily generated from a metal carbene and aLewis base, such as carbonyl compound or sulfide. The highly
GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE 3
reactive ylide then proceeds to undergo further reactions. Forexample, diazoacetic ester (10) is prepared from β-phenylthio-2,3-O-isopropylidene-D-ribofuranose and compound (1). Decom-position of (10) in refluxing benzene containing rhodium(II)acetate results in lactone (11) via an eight-membered cyclicsulfonium ylide intermediate (eq 9).15
HOCH2CO2Et
1Et3N
OH
O
N2
OEt
O
HO
O
O
OEt
32%
C60, toluenereflux, 14 h
32%
toluenereflux, 2 day
94%
(7)
N
SO2
O
N2
NH
SO2
N
SO2
O
H
Rh2(OAc)4
1PhNMe2
90%
83%
90% de
(8)
O
O O
SPhHO
O
O O
SPhO
ON2
Rh2(OAc)4
O
O O
O
O
SPh
1PhNMe2
94% 56%
10
11
(9)
A carbonyl ylide reaction is demonstrated in eq 10. Thediazoester from reaction of compound (1) and allyl alcohol issubsequently treated with Me3SiOTf. The unsaturated silyldia-zoester reacts with various aldehydes or acetone catalyzed byrhodium(II) perfluorobutyrate to afford 1,3-dioxolan-4-ones inmoderate yields via carbonyl ylide intermediates (eq 10).16
OH H
N2
O
O
Me3Si
N2
O
O
O O
H R
O
Me3Si
1Et3N
26% 72%
23–56%
RCHORh2(pfb)4
Me3SiOTf
EtNiPr2
(10)
O–H Insertion Reaction. Metal carbenes easily react withhydroxyl groups to afford O–H insertion products. An example isshown in eq 11. Diazo alcohol (12) readily reacts with reagent (1)to give the corresponding bis(diazo) compound (13). (13) bearstwo differently substituted diazo groups. When rhodium(II)acetate is used as the catalyst, the more reactive diazo system suf-fers selective O–H insertion to afford the monodiazo compound(14). Treatment of compound (14) with methanol and the moreactive rhodium(II) trifluoroacetamide in refluxing tolueneprovides dimethoxy compound (15). (13) is directly transformedinto (15) by treatment with methanol and rhodium(II) trifluoroac-etamide in refluxing toluene (eq 11).17
HO X O
O
PO(OEt)2
N2
O X O
O
PO(OEt)2
N2
O
H
N2
O X O
O
PO(OEt)2
N2
O
OMe
O X O
O
PO(OEt)2
OMe
O
OMe
45–90%
Rh2(OAc)4MeOH (2 equiv)57–90%
Rh2(NHCOCF3)4
MeOH (2 equiv)toluene, 110 °C
63%
Rh2(NHCOCF3)4
MeOH (2 equiv)toluene, 110 °C
76%
12
13
14
15
(11)
1PhNMe2
CH2Cl2, 25 °C
Dimerization Reaction. Dimerization is another commonlyencountered reaction of diazo compounds. Alcohol (16) is ini-tially transformed into diazoester (17) with compound (1) and thenconverted to bisdiazocarbonyl compound (18). The intramolecularcoupling of this mixed diazo compound with a catalytic amount ofRh2(OAc)4 produces a 1:1 mixture of (19) and (20). Furthermore,treatment of (19) with a catalytic amount of iodine quantitativelyconverts (19) to (20) (eq 12).18
4 GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE
O
Me
O
OOMe
OO
OHMe
CO2Me
OMe
CO2Me
O
N2
OMe
O
N2
ON2
Rh2(OAc)4
1PhNMe2
79%
30%
+
cat. I2
16 17
18
19 20
(12)
Reaction with Aldehyde. Reaction of aldehydes (prim-, sec-,and tert-) with the diazoacetamide of N-substituted glycinate, pre-pared from the amino ester and (1), affords β-keto amides in goodto high yields in the presence of Zr(IV) chloride in CH2Cl2.Further treatment with n-Bu4NF in THF leads to N-protected3-acyltetramic acids (eq 13).19
X-NHCH2CO2CH3N2
O
N
X
CO2CH3
R
O
O N
X
CO2CH3
N
OH
O
X
R
O
1Et3N
60–79% 53–79%
96–98%
RCHOZrCl4
n-Bu4NF(13)
N2
O
O
CHO
SnCl2, 61%
O O
O
Cholesterol66%
22
21
23
1Et3N
(14)
Cholesteryl diazoacetate (21) is readily prepared by the treat-ment of cholesterol with compound (1). Reaction of aldehyde (22)with the diazoacetate (21) in the presence of a catalytic amount ofSnCl2 afforded β-oxo ester (23) in good yield (eq 14).20
Other Reactions. Shi and co-workers have reported anunusual reaction of β-hydroxy α-diazo carbonyl compounds withcompound (1). When the reaction of β-hydroxy α-diazo car-bonyl compounds and compound (1) is carried out in the presenceof Et3N, instead of the desired bisdiazo esters, β-(p-tolylsulfonyl)α,β-unsaturated carbonyl compounds or β-(p-tolylsulfonyl)α-diazo esters are obtained in good to high yields (eq 15).21
R
OH
N2
O
R′
R
Ts O
R′
R
Ts O
R′N2
1Et3N
R = aryl
65–90%
65–82%
H
R = alkyl
(15)
Intramolecular C–H insertion reaction of the α-diazoacetylester derived from compound (1) is also reported recently.22 Thecyclization, found to proceed with excellent regio- and stereo-selectivities, and has been used as key step to synthesize natureproducts.
Radioactively labeled α-diazo esters, which are easily preparedfrom the corresponding alcohols and the reagent (1), have beenused as photoaffinity labels.23
Related Reagents. Compound (1) can be converted to reagentsthat undergo further transformation to a variety of diazo carbonylcompounds. Succinimidyl diazoacetate (24) is easily obtained bythe reaction of N-hydroxysuccinimide with compound (1) is a sta-ble, easily stored solid that is highly selective toward diazoacetyltransfer to amines and phenols (eq 16).24
N
O
O
OH N
O
O
O
O
N2
1Na2CO3
47%
24
(16)
GLYOXYLYL CHLORIDE P-TOLUENESULFONYLHYDRAZONE 5
The related phthalimidyl diazoacetate (25) has yielded series ofdiazoacetamides bearing Oppolzer’s camphorsultam chiral auxil-iary (eq 17).25
R CO2H
NNHTs
1. DCC
2. Et3N
THF, rtS
NH
O O
NaH, rt
SN
O O
RO
N2
N OH
O
ON O R
O
N2
O
O
+
R = Ar, CH3
30–61%
25
(17)
Diazo acid chloride (26) can be prepared from compound (1).Chloride (26) is an efficient reagent for preparing diazo dicarbonylcompounds from the corresponding alcohols or amines (eq 18).26
AcNMe2
66%
1
H2C=CHCH2CH2O
O
N2
(Cl3CO)2CO
C5H5N
H2C=CHCH2CH2O
O
N2
Cl
O
26
H2C=CHCH2CH2OH
(18)
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