Photochemical electron transfer mediated addition of naphthylamine derivatives to electron-deficient alkenes

ARTICLE

pubs.acs.org/joc

Photochemical Electron Transfer Mediated Addition of

Naphthylamine Derivatives to Electron-Deficient Alkenes

Rabih Jahjah,^†Abdoulaye Gassama,^†Frꢀedꢀeric Dumur,^†Siniꢁsa Marinkoviꢀc,^†Sabine Richert,^‡

Stephan Landgraf,^‡Aurꢀelien Lebrun,^§Cyril Cadiou,^||Patrice Sellꢂes,^zand Norbert Hoﬀmann*^,†

^†Equipe de Photochimie and Equipe Chimie de Coordination, Institut de Chimie Molꢀeculaire de Reims, UMR 6229 CNRS et

Universitꢀe de Reims Champagne-Ardenne, UFR Sciences, B.P. 1039, 51687 Reims, France

^§Institut de Chimie Molꢀeculaire de Reims, UMR 6229 CNRS et Universitꢀe de Reims Champagne-Ardenne, UFR Sciences,

B.P. 1039, 51687 Reims, France

^‡Institute of Physical and Theoretical Chemistry, Graz University of Technology, Stremayrgasse 9, 8010 Graz, Austria

^zSyngenta Crop Protection Muenchwilen AG, 4332 Stein, Switzerland

S Supporting Information

b

ABSTRACT: Using photochemical electron transfer, N,N-di-

methylnaphthylamine derivatives are added to R,β-unsaturated

carboxylates. The addition takes place exclusively in the R-

position of electron-deﬁcient alkenes and mainly in the 4-posi-

tion of N,N-dimethylnaphthalen-1-amine. A minor regioisomer

results from the addition in the 5-position of this naphthylamine.

A physicochemical study reveals that the ﬂuorescence quenching

of N,N-dimethylnaphthalen-1-amine is diﬀusion-controlled and

that the back electron transfer is highly eﬃcient. Therefore no transformation is observed at lower concentrations. To overcome this

limitation and to induce an eﬃcient transformation, minor amounts of water or another proton donor as well as an excess of the

naphthylamine derivative are necessary. A mechanism involving a contact radical ion pair is discussed. Isotopic labeling experiments

reveal that no hydrogen is directly transferred between the substrates. The hydrogen transfer to the furanone moiety observed in the

overall reaction therefore results from an exchange with the reaction medium. An electrophilic oxoallyl radical generated from the

furanone reacts with the naphthylamine used in excess. Concerning some mechanistic details, the reaction is compared with radical

and electrophilic aromatic substitutions. The transformation was carried out with a variety of electron-deﬁcient alkenes. Sterically

hindered furanone derivatives are less reactive under standard conditions. In a ﬁrst experiment, such a compound was transformed

using heterogeneous electron transfer photocatalysis with TiO₂.

’ INTRODUCTION

chemistry of organic molecules. Kinetics of the photochemical

electron transfer are determined by Marcus theory.^6,8Recently,

we used such processes to develop an eﬃcient method for

the addition of simple tertiary amines to alkenes.^9,10In this

case, electron transfer sensitizers such as electron donor sub-

stituted aromatic ketones were used as eﬃcient homogeneous

catalysts.^11,12The same reaction was carried out with inorganic

semiconductors such as TiO₂or ZnS as eﬃcient heterogeneous

photocatalysts.¹³In cases of homogeneous photocatalysis, initi-

ally generated radical ions undergo proton transfer from the

radical cation to the radical anion, thus generating neutral

radicals. The latter intermediates undergo radical chain reactions.

Such reactions can be controlled by addition of thiocarbonyl

compounds, which reversibly add to the radical intermediates

and thus control the outcome.^14,15These transformations have

also been successfully applied to radical polymerization.^16,17In a

variety of such photocatalytic reactions very interesting for

Photochemical reactions considerably enrich the methodol-

ogy in organic synthesis.¹Frequently, mild reaction conditions

are applied and no activating reagents (acids, bases, metals, etc.)

are necessary, which opens perspectives in the context of a

sustainable chemistry.²The electron conﬁguration completely

changes when molecules are electronically excited, and thus their

chemical properties also signiﬁcantly change with respect to the

ones in the ground state.³For instance, electron transfer between

two molecules in the ground state is possible only when the

energy of the highest occupied molecular orbital (HOMO) of the

donor molecule is energetically higher than the lowest unoccu-

pied molecular orbital (LUMO) of the acceptor molecule. The

electron transfer is then exothermic. When one of these reaction

partners is photochemically excited, electron transfer is also

possible in cases where the ground state HOMO of the donor

molecule is energetically lower than the LUMO of the acceptor.

The endothermicity of a corresponding electron transfer in the

ground state is compensated by the excitation energy.^4ꢀ7Thus

photochemical electron transfer considerably enriches the redox

Received: May 26, 2011

Published: August 01, 2011

r

2011 American Chemical Society

7104

dx.doi.org/10.1021/jo201080m J. Org. Chem. 2011, 76, 7104–7118

|

The Journal of Organic Chemistry

ARTICLE

synthetic applications, sacriﬁcial electron donors or acceptors are

needed.^11,18

Scheme 1. Photochemical Addition of Naphthylamine

Derivative 1 to Furanone 2

All of these reactions are more or less complex processes

leading to the formation of a carbonꢀcarbon bond. Reactions

have also been reported in which such a bond formation is

induced by photochemical electron transfer between the two

reaction partners without intervention of a sacriﬁcial electron

donor or acceptor or a sensitizer. For instance, tertiary amines

have been added to electronically excited R,β-unsaturated

ketones in this way.^19,20Photochemical analogues of the Suzuki,

Sonogashira, or Heck reactions as well as addition of aromatic

compounds to alkenes have been carried out by excitation of

electron-rich benzene derivatives.²¹Reactions involving direct

photochemical electron transfer between the substrates have

been performed with phthalimide derivatives.^10,22All of these

transformations are particularly interesting since they do not

need any metal activation. In many cases, however, leaving

groups are involved, which leads to the formation of byproduct.

In this context, we were interested in reactions in which neither

leaving groups nor electron transfer sensitizers are involved.

Thus only photochemical electron transfer between the sub-

strates will induce the transformation. Herein, we report on the

regioselective addition of naphthylamine derivatives to electron-

deﬁcient alkenes. In this transformation, the alkene is formally

inserted in a relatively strong aromatic CꢀH bond. Currently, in

the ﬁeld of organometallic chemistry, such transformations are

intensively investigated in the context of “CꢀH activation”.^23ꢀ25

Activation of thermodynamically stable CꢀH bonds is also

intensively studied in biochemistry or chemical biology.²⁶

Table 1. Irradiation Time and Yields of the Reaction between

Compounds 1 and 2 Depending on the Excess of Amine 1 in

the Reaction Mixture (Scheme 1)

amine concn

(mol L^ꢀ1

)

irradiation time

(h)

yield

(%)

entry

amine equiv

1

2

3

4

50

15

10

5

3.1

1.5

1.1

0.6

6

92

89

62

a

17

24

^aOnly traces of the products were detected by NMR.

’ RESULTS AND DISCUSSION

electrophilic substitutions in the ground state of such naphtha-

lene derivatives carrying an electron-donating substituent in the

1-position, the transformation in position 2 dominates over the

one in position 5.^35ꢀ38

We started our investigation with the reaction of N,N-

dimethylnaphthalen-1-amine 1 with furan-2[5H]-one 2 in acet-

onitrile as solvent and in the presence of water (Scheme 1).

Naphthylamine 1 was added in excess. The best results were

obtained when a 0.1 M solution of furanone 2 was irradiated in

the presence of 15 equiv of the amine 1 (Table 1, entry 2). Larger

amounts (entry 1) do not improve the yields. No signiﬁcant

transformation was observed when the proportions of substrates

were inversed (furanone 2 (1.5 mol L^ꢀ1) with respect to the

naphthylamine 1 (0.1 mol L^ꢀ1)). Small amounts of water were

crucial for the transformation. Best results were obtained when

the reaction mixture contained 4% of water. (In the case of higher

water amounts, the reaction mixture became heterogeneous and

naphthylamine 1 deposited.) Two regioisomers 3a,b were ob-

tained in a ratio of 9/1. Surprisingly when compared to the large

majority of ground state reactions^27,28of R,β-unsaturated carbo-

nyl or carboxyl compounds, the addition of 1 occurred only in the

R-position of furanone 2. In similar reactions, the β-position of 2

is more electrophilic. When compared to well established

reactivity of R,β-unsaturated carboxyl compounds, it must be

stated that R-functionalization of such compounds, for example,

in the case of the BaylisꢀHillman reaction,^28,29is more diﬃcult.

Recently, a similar Lewis acid catalyzed reaction was published.³⁰

In the electronically excited state of furanones and depending

on the mechanism, selective CꢀC bond formation occurs in

the R-position of furanones³¹or R,β-unsaturated carbonyl

compounds.^32ꢀ34In these cases, the R-regioselectivity is essen-

tially linked to the biradical structure of the T₁(³ππ*) state of

such compounds. It is also surprising that the minor regioisomer

3b results from addition in the 5-position of compound 1. In

To obtain mechanistic information, isotopic labeling experi-

ments were carried out. During the transformation, a hydrogen

atom in position 4 of the naphthylamine derivative 1 is removed

(formation of the major isomer 3a in a formal electrophilic

aromatic substitution) while a hydrogen atom is added in the

β-position of furanone 2 (Scheme 2). Deuterium labeling may

lead to information about the origin of the hydrogen in this

position, and more general mechanistic conclusions should also

be possible. We ﬁrst checked whether hydrogen in the β-position

of products 3a,b may originate from the naphthalene compound

1. However, when deuterated compounds 4 or 5 were trans-

formed, no deuterium was detected in the β-position of the

reaction products (Scheme 2, eq 1). Deuterium transfer to the

furanone did not occur either from the methyl group or from

the most reactive 4-position of the naphthylamine derivative.

The yields and the ratio of regioisomers did not change when the

isotopically marked compounds were transformed. These results

with isotopic labeling are quite diﬀerent from those that we have

previously published in the context of sensitized photochemical

electron transfer reactions.^39ꢀ41To check whether hydrogen is

transferred from the reaction medium, ﬁrst acetonitrile-d₃was

used. In this case, no deuterium was detected on the lactone

moiety of the products. However, when D₂O was used, deuter-

ium incorporation was observed in the β-position of the lactone

moiety of products 8a,b (incorporation of one deuterium >90%).

We concluded that a protic solvent or cosolvent is necessary for

7105

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Scheme 2. Photochemical Addition of Deuterated Naphthylamine Derivatives 4 and 5 to Furanone 2^a

^aThe conversion was complete after 6 h of irradiation.

the successful transformation. Two additional experiments con-

ﬁrmed this interpretation. When compounds 1 and 2 were

irradiated in CD₃OD, deuterated compounds 8a,b were ob-

tained in 85% yield and with the same ratio of regioisomers; 10 h

of irradiation was needed for complete conversion. No conver-

sion was observed when water-free acetonitrile was used. We also

observed a slow conversion in the presence of water traces in

acetonitrile. The use of protic solvents or cosolvents, water in

particular, is essential for the reactivity.

Similar observations concerning regioselectivity or deuterium

transfer have been made in photochemical transformations of

electron-rich aromatic compounds with acrylates.^42,43In these

previously reported transformations, the reaction competes with

[2 + 2] or [2 + 3] photocycloaddition.⁴⁴

Using the Norrish type II reaction of butyrophenone as

actinometer,^45ꢀ47we have measured a product quantum yield

of 0.1 for the optimized reaction conditions (Table 1, entry 2). It

must be pointed out that the quantum yield decreases signiﬁ-

cantly when the naphthylamine concentration is diminished, as

illustrated by the reaction times and yields in Table 1, or when the

proton source is removed.

To get insight into the primary photophysical steps, physico-

chemical studies have been carried out. The quenching reaction

of N,N-dimethyl-1-naphthylamine 1 with 2[5H]-furanone 2 was

found to be diﬀusion controlled. Steady state and time-resolved

ﬂuorescence measurements yielded identical values of 2.0 ( 0.2 ꢁ

10¹⁰M^ꢀ1s^ꢀ1for the quenching constant, revealing that the

nature of the quenching is purely dynamic according to the

simple EinsteinꢀSmoluchowski equation (k_diﬀ= 8RT/3η).

Under the applied conditions (solution in pure acetonitrile at

25 °C), the ﬂuorescence lifetime of the ﬂuorophore amounts to

4.4 ns (under Ar), whereas for the ﬂuorescence quantum yield a

value of 0.20 was obtained. No photoproduct formation could be

observed. We therefore assume that eﬃcient back- electron

transfer occurs.

indication for complex formation in ground or excited state, so

that exciplex formation is not thought to occur under the

conditions applied. Within experimental error, the quenching

constants determined from quantum yields and lifetime mea-

surements are identical to the ones obtained in the case where no

water was added. The observations indicate that water has no

inﬂuence on the primary quenching step.

To favor excited state complex formation, it was attempted to

lower the dielectric constant of the solution by studying the

reaction in solvents or solvent mixtures of diﬀerent permittivity.

The following solvents were tested but all of them were found to

react with the excited state of the ﬂuorophore, indicated by a

decrease in both, the ﬂuorescence lifetime as well as the quantum

yield: propyl acetate, benzyl acetate, methyl-iso-butylketone,

1-hexanol, 1-butanol, butanone, toluene, THF, n-hexane, tert-

butyl benzene.

On the basis of our observations, we suggest the mechanism

depicted in Scheme 3. After photochemical excitation of naph-

thylamine 1, an electron transfer may take place from the amine

1 to the furanone 2 leading to a radical ion pair. Using the

Weller equation,^4,5,48the ΔG_ETof this photochemical is

estimated to ꢀ0.37 eV (ꢀ8.5 kcal/mol), which is in agreement

with our previous observations of fast ﬂuorescence quenching

of amine 1.⁴⁹

ΔG_ET¼ E°ðD^þ=DÞ ꢀ E°ðA=A^ꢀÞ ꢀ E_0ꢀ0ꢀ w

ð3Þ

The redox potentials of the substrates have been determined

by cyclic voltametry (vs ferrocene/ferrocenium): E_p(1⁺/1) =

+0.39 V, E_p(2/2^ꢀ) = ꢀ2.75 V. The energy gap between the

frontier orbitals (E_0ꢀ0) approximately corresponds to the excita-

tion energy, which can be determined by UVꢀvis spectroscopy.

Especially in cases of low Stokes shifts, a better value of the

HOMO/LUMO energy diﬀerence is obtained when the 0ꢀ0

transition between the S₀and the S₁potential energy surface is

determined from UVꢀvis absorption and ﬂuorescence spectra

(Figure 1).⁵⁰The corresponding energy of 3.39 eV is determined

from the intersection (λ_inter= 365 nm) of the absorption and the

Upon addition of 1% of bidistilled water to the ﬂuorophoreꢀ

quencher solutions, no spectral changes were detected. The

recorded absorption and ﬂuorescence spectra do not give any

7106

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Scheme 3. Mechanism of the Photochemical Electron Transfer Mediated Addition of Naphthylamine Derivative 1 to Furanone 2

competitive trapping process is needed. Protonation of the

radical anion by the reaction medium fulﬁlls this task and leads

to the radical cation I and the oxoallyl radical II. Obviously,

proton transfer from the radical cation to the radical anion^19,31,52

in the radical ion pair does not occur. It has been suggested that a

very polarized exciplex may be protonated or deuterated, leading

directly to the formation of intermediates such as I and II.⁴²

However, as photochemical electron transfer is exothermic and

given the polarity of the solvent applied, we assume the formation

of a radical ion pair. Furthermore, we have no evidence for the

formation of such an exciplex intermediate. Electrophilic oxoallyl

radicals such as II are easily trapped by nucleophilic reaction

partners.^14,46,53In the present case, this occurs through addition

of the naphthylamine derivative 1, which is therefore needed in

excess. Despite the trapping process and as indicated by the

product quantum yield (Φ = 0.1) and the eﬃcient ﬂuorescence

quenching of 1 by the furanone 2, about 90% of the radical ion

pair reacts via back electron transfer to regenerate the substrates

1 and 2. As in the case of R-aminoalkyl radicals,^13,39,54the

resulting intermediate III is easily oxidized, and after deprotona-

tion, the ﬁnal product 8a is obtained. Although the product yield

of the overall reaction is high, no details on the last mechanistic

step can be indicated here. For instance, the oxidation of

intermediate III might occur by electron transfer from this

Figure 1. Absorption and normalized ﬂuorescence spectra of naphthy-

lamine derivative 1.

normalized emission spectra. The value for w is +0.12 eV. This

term corresponds to the free enthalpy gained by bringing the ions

to encounter distance in acetonitril as solvent.⁵¹In contrast,

cyclic voltametry is considered to take into account free ions.

The productivity of photochemical electron transfer mediated

reactions frequently suﬀers from back electron transfer, which

leads to the regeneration of the substrates. In our case, this

electron transfer is eﬃcient. To induce a chemical reaction, a

7107

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Scheme 4. General Mechanism of Electrophilic Substitution

Involving Single Electron Transfer

Scheme 6. Electrophilic Aromatic Substitution with Elec-

trophilic Radical II and Naphthylamine Derivative 1 Involving

Single Electron Transfer As Outlined in Scheme 4

Scheme 5. Mesomeric Structures of the Radical Anion of

Furanone 2

ref 13) and is protonated in its β-position. Obviously, the radical

anion intermediate in this heterogeneous reaction is better

represented by the mesomeric structure B (Scheme 5). In

analogy to these previous observations, we conclude that pro-

tonation of the furanone part in the present reaction also occurs

in a conﬁned structure in which the furanone radical anion is

ﬁrmly bound in an ion pair to the naphthylamine partner as

depicted in Scheme 3. As already mentioned above, a proton-

ation in the β-position of acryl derivatives was discussed in cases

where the acrylate is bound in a polarized exciplex.⁴²

species to the radical cation I. Similar inter- and intramolecular

radical aromatic substitutions have been reported several times in

the literature^55ꢀ57(see also ref 39).

The overall reaction as depicted in Scheme 1 resembles an

electrophilic aromatic substitution.^35,58Although frequently

supposed in the past,⁵⁹only recently has electron transfer been

proven to be involved in some of these reactions.⁶⁰In particular,

nitration and nitrosylation was discussed in this context.^61ꢀ63In

view of these results, the electron transfer from the aromatic

compound ArH to the electrophile E⁺takes place (Scheme 4).

Radical combination leads to the σ-complex (Wheland inter-

mediate). Often the electron transfer step is rate-limiting in the

overall reaction. In our case (Scheme 3), such an electron transfer

at the ground state is endothermic (E = +3.02 eV). Between the

substrates, only photochemical induced electron transfer is

exothermic, thus enabling the reaction. Furthermore, it should

be pointed out that in our case a neutral but electrophilic oxoallyl

radical adds to an electron-rich aromatic system and a σ-complex

intermediate is formed after oxidation of the resulting inter-

mediate III (see below).

When compared to electrophilic substitution, one must also

point out that the electrophilic site of R,β-unstaturated lactone is

the β-position. Therefore, one should observe reaction at this

position, which would also be in accordance with the Michael

reaction as already mentionned.^27,28,38The observed regiospe-

ciﬁc R-addition in our reaction is due to previous protonation of

the radical anion in the β-position as outlined in Schemes 2 and 3.

To explain this unusual selectivity, the structure of the radical

anion must be discussed. This species possesses two main

mesomeric structures, A and B (Scheme 5). Protonation is

expected at the enolate oxygen (A) since this atom is the most

electronegative one. In a previous mechanistic study using

deuterium labeling, an alkoxyfuranone molecule in solution

was reduced to a radical anion.^9,39,41The latter was deuterated

at the enolate oxygen, and after tautomerization of the enol,

deuterium was detected in the R-position of the lactone. The

same photochemical reaction was carried out with inorganic

semiconductors such as TiO₂or ZnS in their function as

photochemical electron transfer sensitizers.^40,41In this case,

the same radical anion of an alkoxyfuranone is adsorbed at the

surface of a negatively charged semiconductor particle (see also

Naphthalene derivatives carrying an electron donor substitu-

ent in position 1 generally undergo electrophilic substitution

mainly in the 4-position and to a less extent in the 2-

position.^35,36,38In the present case, however, the minor product

results from a transformation in the 5-position (Schemes 1 and 2).

Similar unusual regioselectivities have also been observed in

some radical aromatic substitution reactions with naphthalene

derivatives.⁵⁷Such results are explained by a two-step mechanism

as depicted in Scheme 6. As shown in the general mechanism

(Scheme 4), single electron transfer is involved that leads to

the radical cation I and to the enolate IV. In this context, it should

be pointed out that radicals carrying electron-withdrawing

substituents such carbonyl or carboxyl groups are easily

reduced.⁶⁴The corresponding neutral σ-complexes IIIa and IIIb

are formed by charge combination. In such a step, the regios-

electivity is controlled by the charge or the electron density in the

intermediates. It has been shown previously that in radical

cations of naphthalenes carrying an electron-donor substituent

in the 1-position the positive charge density may be higher in

position 5 than in position 2.^57,65We have determined the overall

electron densities in the radical cation I using HF calculations

(Figure 2). In positions in which electrophilic substitution can

occur, the lowest electron density is detected in position 4

(ꢀ0.106). The main product IIIa results from a reaction in this

position. The electron density in position 2 (ꢀ0.172) is sig-

niﬁcantly higher than that in position 5 (ꢀ0.127). Therefore, the

formation of the minor regioisomer IIIb results from a transfor-

mation in the latter position. A relatively low electron density is

also detected in position 8 (ꢀ0.128). Most probably, due to

steric hindrance, no reaction occurs in this position.^66,67

Compound 3a is a 2-(4-(dialkylamino)naphthalen-1-yl)pro-

panoic acid derivative. Such compounds possess a variety of

pharmaceutical activities.⁶⁸To obtain a ﬁrst glance of the scope

of the reaction, structural variations have been carried out on the

7108

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Scheme 8. Dia- and Regioselective Addition of Naphthyla-

mine Derivative 1 to Furanones 11 and 12 Carrying a

Subsitutent in Position 5

Figure 2. Overall charge distribution in the radical cation I.

Scheme 7. Photochemical Addition of Naphthylamine Deri-

vative 1 to Furanone 9 Carrying a Methyl Group in the R

Position

substrates⁷⁰and also the addition of the corresponding oxoallyl

radical with the naphthylamine 1. This addition of 1 occurred

preferentially anti with respect to the substituent in position 5

leading to compounds 13a,b and 14a,b. In both cases, the

diastereoisomers were separated by column chromatography.

The corresponding fractions contained a mixture of regioisomers

a and b. For this 1,3 chiral induction, the diastereoselectivity was

moderate when compared to the 1,2 chiral induction with

comparable compounds (for instance, 1,2 chiral induction in

the addition reactions at the β-position).^71ꢀ73The ratio of

regioisomers was almost the same for the major (13a,b and

14a,b) and the minor diastereoisomer (15a,b and 16a,b).

Methylcrotonate 17 and dimethylfumarate 18 have success-

fully been transformed with amine 1 under the same reaction

conditions (Scheme 9, eq 4 and 5). In the case of 17, the

expected adducts 19a,b have been isolated in a 9/1 ratio of

regioisomers. The reaction of 18 also lead to the expected

adducts 20a,b with the a comparable ratio of regioisomers

(Scheme 9, eq 5). Additionally, compound 21 was formed in

minor amounts. This product resembles to compounds, that

have been obtained by photochemically induced radical tan-

dem addition cyclization reactions^39,40,71(see also refs 74 and

75). Under the applied reaction conditions, its formation can

be explained by the mechanism depicted in Scheme 10. After

photochemical excitation of the naphthylamine derivative 1,

electron transfer occurs according the mechanism depicted in

Scheme 2 leading to the radical ion pair V and VI. Instead of

protonation of the radical anion VI by the reaction medium,

proton transfer occurs from the radical cation V to VI. This

competitive acid base reaction may be favored by the presence

of two basic centers (ester functions) in the radical anion VI.

substrates. First, the structure of the furanone was modiﬁed by

addition of substituents in diﬀerent positions. When 3-methyl-

2[5H]-furanone 9 transformed under the optimized reaction

conditions, compound 10 was isolated in moderate yields

(Scheme 7). Furthermore, the reaction was considerably slower

when compared to the transformation of furanone 2. After 15 h

of irradiation, only 62% of 9 was transformed and the adduct 10

was isolated with yield of 35% (selectivity 57%). Only one

regioisomer was obtained resulting from a selective reaction in

position 4 of the naphthylamine 1. The reduced reactivity may be

explained by the increased steric hindrance of the R-position in

compound 9. Nevertheless, it must be pointed out that it remains

suﬃcient to establish a quaternary sp³-hybridized center carrying

4 carbon substituents.⁶⁹

We next investigated the reaction of furanones 11 and 12

carrying a substituent in the 5-position with the naphthylamine

derivative 1 (Scheme 8, Table 2). Lower yields were obtained

when compared to the parent compound 2 (Scheme 1, Table 1).

On the basis of the previous mechanistic discussion, this ob-

servation may be explained by a hindered formation of the key

intermediates such as the radical ion pair (compare Scheme 3).

Steric eﬀects reduce the interaction of the π systems of the

7109

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Table 2. Diastereoselective Addition of 1 with Furanones 11 and 12 Carrying a Substituent in Position 5 (Scheme 7)

major diastereoisomer (anti addition)

minor diastereoismer(syn addition)

R

a/b^a

yield (%)

a/b^a

yield (%)

ratio of diastereoisomers

Me

11

12

11/1

10/1

45

25

10/1

13

10

3.5

2.5

OEt

^aRatio of regioisomers.

Scheme 9. Photochemical Addition of Naphthylamine Derivative 1 to Acyclic R,β-Unsaturated Esters 17 and 18

Scheme 10. Mechanism of Formation of Minor Product 21

Thus the neutral radicals VII and VIII are formed. The

R-aminoalkyl radical VII easily adds to the electron-deﬁcient

double bond of 18 to form intermediate IX.^53,76Cyclization

(X) and rearomatization lead to the ﬁnal product 21. In

principal, the fumaric ester 18 may also act as electron transfer

sensitizer.^11,39,40However, since the absorption coeﬃcient of

18 at λ = 350 nm is very low and 1 possessing a higher one at

this wavelength is used in excess, such a mechanism should be

excluded.

We also investigated the transformation of N,N-dimethyl-

naphthalen-2-amine 22 (Scheme 11, eq 6) which is a regioisomer

of 1. When 22 was irradiated under standard conditions in the

presence of furanone 2, compound 23 was obtained in high yield

as the sole reaction product. A CꢀC bond was formed between

the carbon 1 of the naphthylamine derivative 22 and the R

carbon of furanone 2. The reaction rate was lower when

compared to the transformation of 1 (Scheme 1, Table 1) which

may be explained by an increased steric hindrance. Indeed, in

7110

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

Scheme 11. Photochemical Reactivity of Naphthylamine

Derivatives 22 and 24 with Furanone 2 under Standard

Conditions

furanone 2 (Scheme 5) and in particular the mesomeric structure

B plays an important role.⁴⁰As outlined above, this structure in

the radical ion pair (Scheme 3) explains the regioselective

protonation in the β-position of this intermediate. On the basis

of these mechanistic similarities with a common intermediate

possessing the same polarization, we concluded that TiO₂

heterogeneous photocatalysis might also enable the addition of

naphthylamine 1 to less or unreactive alkenes. To prove this

hypothesis, we performed the reaction of naphthylamine 1 with

menthyloxyfuranone 25 (Scheme 12). Using the standard reac-

tion conditions discussed above, no transformation took place.

Using homogeneous photocatalysis with Michler’s ketone as

electron transfer sensitizer,³⁹the transformation could not be

carried out.⁴⁷However, when both substrates 1 and 25 were

irradiated in the presence of TiO₂(16 mg, 0.2 mmol in 20 mL), a

selective transformation was observed and the two diastereo-

meric adducts 26 and 27 were obtained in a ratio of 1/3.3 (53% of

diastereomeric excess), which is comparable to that observed in

the homogeneous reaction with furanones 11 and 12 (Scheme 8,

Table 2). A higher excess of the amine 1 was necessary, and no

addition of water or another proton source was required to

induce the transformation. In particular, the addition of water

would have favored photochemical degradation of the organic

substrates.⁷⁹As already pointed out above, for this 1,3 chiral

induction the diastereoselectivity was moderate when compared

to that of the 1,2 chiral induction with comparable compounds,

for instance, in addition reactions in the β-position.^71ꢀ73

For the moment, it is diﬃcult to propose a mechanism. For

similar transformations, it has been suggested that after forma-

tion of an electron hole pair in the semiconductor particle by light

absorption, electron transfer occurs from the donor molecule to

the particle, which quenches the hole.^81ꢀ83A critical step is the

transfer of the electron in the conduction band to the acceptor

molecule thus leading to the formation of a radical anion. A

characteristic observation in such reactions is the formation of a

reduction side product of the acceptor molecule.⁸³In our case,

such a product (28) was indeed observed (Scheme 12).⁸⁴On the

other hand, the redox potential of 25 (E(25/25^ꢀ) = ꢀ2.52 V (vs

fercene/ferrocenium)) seems not to allow such an electron

transfer from the conduction band of TiO₂(E_cb= ꢀ1.2 V (vs

fercene/ferrocenium)).⁸⁵In the present case, the TiO₂contain-

ing suspension was irradiated in the presence of large amounts of

amine 1, leading to eﬃcient electron transfer from the amine to

the semiconductor particle. In the absence of an appropriate

acceptor, appreciable negative charge can thus be built up on the

particle, which induces also the otherwise less favorable reduc-

tion processes.^85,86The electron transfer from the conduction

band to the alkoxyfuranone 25 may also be facilitated by the fact

that it is adsorbed at the particle surface via an interaction of the

carboxyl oxygen with a Ti ion.

NMR spectra of compound 23 which was recorded at room

temperature, conformational rigidity (atropisomerism⁷⁷) was

detected. On the other hand, the reactivity concerning electro-

philic aromatic substitutions at the 1 position is particularly high

in such compounds.^35,37,78

In the case of the transformation of N,N-dimethylnaphthalen-

1-amine 1, we observed the favored addition of the furanone 2 in

position 4 and a reduced reactivity in position 5 (Scheme 1). We

wonder whether we could direct the major reactivity into

position 5 or eventually into positions 2 or 7 by blocking position

4 by a methyl substituent in compound 24 (Scheme 11, eq 7).

These positions are more or less reactive in electrophilic

substitutions.^35ꢀ37However, under the standard reaction con-

ditions and after 20 h of irradiation, no transformation was

observed.

As already pointed out, sterically hindered and less planar

electron-deﬁcient alkenes were hardly transformed under the

described reaction conditions (Scheme 8, Table 2). Obviously,

the formation of the key intermediates (radical ion pair) and

addition of the oxoallyl radical (compare II in Scheme 2) are

diﬃcult in such cases. Thus menthyloxyfuranone 25 could not

successfully be transformed, although the photochemical elec-

tron transfer is more exothermic (ΔG_ET= ꢀ0.60 eV) than in

the case of 2 (ΔG_ET= ꢀ0.39 eV). The reduction potential

of furanone 25 has been determined by cyclic voltammetry

(vs ferrocene/ferrocenium) in acetonitrile: E_p^red(25/25^ꢀ) =

ꢀ2.52 V.

Alternatively, an electron transfer from the excited naphthy-

lamine derivative 1 to the adsorbed furanone 25 may be con-

sidered. The resulting radical ion pair should react in the usual

way (compare Scheme 3). In this context it should be noted that

1 is used in excess (2.5 mol L^ꢀ1). Further investigations are

necessary to depict a more precise mechanism.

Structure Determination of Photochemical Products.

Compounds 3a,b (Scheme 1) have been isolated as a chroma-

tographically inseparable 9/1 mixture of regioisomers. The

determination of the position of the butyrolactone fragment

on the naphthylamine moiety of each isomer is crucial and has

been carried out by NMR spectroscopy (500 MHz proton

We wonder whether such compounds may be transformed

when photocatalysis is applied, and we were particularly inter-

ested in using heterogeneous photocatalysis with inorganic

semiconductors such as TiO₂. Generally, such conditions are

applied for puriﬁcation of waste waters.⁷⁹However, this hetero-

geneous photocatalysis was also applied to organic synthesis.⁸⁰

During our studies on the radical addition of tertiary amines to

electron-deﬁcient alkenes¹³making use of this photocatalysis, it

became evident that the structure of the radical anion of the

7111

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

a

Scheme 12. Addition of Naphthylamine Derivative 1 to Menthyloxyfuranone 25 Using Heterogeneous Photocatalysis with TiO₂

^aThe yields are based on the conversion.

Table 3. NMR Data of Compound 3a (Scheme 1)

Table 4. NMR Data of Compound 3b (Scheme 1)

¹³C

¹H

multip, J

HMBC

¹³C

¹H

multip, J

HMBC

(ppm)

(Hz)

attribution correlation

(ppm)

(Hz)

attribution

correlation

178.3

150.9

132.4

129.3

127.4

Q

2

177.9

151.8

133.4

132.6

129.5

Q

2

1⁰

10⁰

9⁰

4⁰

6⁰

3⁰

8⁰

7⁰

5⁰

2⁰

5

1⁰f 8⁰,2⁰,3⁰

10⁰f 8⁰, 3⁰

9⁰f 5⁰, 2⁰

1⁰

5⁰

10⁰

9⁰

3⁰

6⁰

7⁰

8⁰

4⁰

2⁰

5

5⁰f 4⁰, 7⁰

10⁰f 8⁰, 3⁰, 6⁰

9⁰f 2⁰, 7⁰, 4⁰

4⁰f 5⁰, 2⁰, 3

126.3 CH 7.53

m

126.4 CH

125.1 CH

124.6 CH

124.5 CH

117.7 CH

114.1 CH

7.47

7.38

7.47

8.28

7.56

7.13

4.48

2.89

4.49

2.80

2.42

dd, 7.7, 8.2

125.3 CH 7.30 d, 7.8

d, 6.9

125.2 CH 8.33

125.1 CH 7.53

123.4 CH 7.86

m

dd, 6.9, 8.5

d, 8.5

d, 8.2

113.6 CH 7.05 d, 7.8

66.7 CH₂4.48 ddt, 4.8, 8.0, 9.0

d, 7.5

a

CH₂

ddt, 4.8, 8.0, 9.0

45.2 CH₃2.89

42.6 CH 4.44

s

1⁰⁰

45.3 CH₃

43.2 CH

31.6 CH₂

s

1⁰⁰

m

3

m

3

31.5 CH₂2.82 dddd, 4.8, 7.1, 9.0, 12.9

2.42 dq (virt), 12.9, 8.0

4

^aUncertain ¹³C NMR attribution

resonance frequency). Using additionally two-dimensional

NMR techniques (COSY, HSQC, HMBC), chemical shifts of

almost all protons and ¹³C atoms have been detected and

attributed (Tables 3 and 4). HMBC correlations as well as the

coupling motives of protons 3⁰in 3a and 3b and of proton 6⁰in

3b are particularly indicative. The addition of the naphthyla-

mine derivative in the 3- or R-position of the furanone is also

detected by the HMBC correlation. The structures of syn and

anti isomers (13a and 15a) have been determined with NOESY

correlations (Figure 3).

Figure 3. Structure determination of the diastereoisomers 13a and 15a

(compare Scheme 9) by detection of NOESY correlations.

’ CONCLUSION

N-dimethylnaphthalen-1-amine by the furanone is diﬀusion-

controlled, and the back electron transfer in the resulting radical

ion pair is highly eﬃcient. Therefore, no transformation is

observed at lower substrate concentrations. To induce a chemical

The addition of naphthylamine derivatives to the electron-

deﬁcient double bond of furanones has been eﬃciently carried

out with yields up to 90%. Fluorescence quenching of N,

7112

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

reaction in this inherently unreactive system, two reaction

parameters must be modiﬁed: water or another proton source

must be added, and the naphthylamine must be used in excess in

the reaction mixture. Under these conditions the transforma-

tion becomes highly eﬃcient. The radical anion of the furanone

is protonated, and the resulting electrophilic oxoallyl radical

reacts with N,N-dimethylnaphthalen-1-amine by radical aro-

matic substitution. Thus back electron transfer in the radical ion

pair becomes less dominant. It should further be pointed out

that this transformation involving aromatic CꢀH activation

does not need chemical activation with metal compounds or

other reagents. Light acts as traceless reagent. The reactivity

decreases when sterically encumbering or conformationally

mobile substituents are attached to the electron-deﬁcient

alkene. First investigations indicate that in such cases, the

reactivity may be enhanced when heterogeneous photochemi-

cal electron transfer catalysis is applied with inorganic semi-

conductors such as TiO₂.

brown. Deuterium oxide (16.7 mL) was then added. After 3 h at ꢀ30 °C

the reaction mixture was additionally stirred overnight at room tempera-

ture. Water (15 mL) was added, and the mixture was extracted three times

with ether (20 mL). The organic phases were dried with MgSO₄. After

evaporation of the solvent, the residue was distilled. Yield: 13.87 (92%).

¹H NMR (500 MHz, CDCl₃) δ 7.11 (d, J = 7.4 Hz, 1H), 7.44 (d, J = 7.4

Hz, 1H), 7.51 (m, 1H), 7.54 (m, 1H), 7.87 (dd, J = 7.6/1.4 Hz, 1H), 8.30

(dd, J = 8.0/1.4 Hz, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 44.4 (sept, J =

20.2 Hz), 113.9, 122.6 (t, J = 24.4 Hz), 124.2, 125.2, 125.8, 125.8, 128.4,

128.9, 134.9, 150.9; IR (ﬁlm) ν 2939, 1582 cm^ꢀ1. HRSM (ESI + H): m/z

calcd for C₁₂H₇D₇N 179.1566, found 179.1557 [M + H]⁺.

Standard Procedure for Photochemical Transformation

of Naphthylamine Derivatives with Electron-Deficient Al-

kenes under Homogeneous Reaction Conditions. A solution

of the R,β-unsaturated ester (1 equiv), the naphthylamine derivative (15

equiv), and water (0.38 mL) in acetonitrile (7 mL) was purged with

argon for 20 min before being irradiated until maximal conversion. After

evaporation of solvent and water, the residue was purified by flash

chromatography (eluent, ethyl acetate/petroleum ether, 1:9). In most

cases, mixtures were isolated. Signal attributions in NMR spectroscopy

were carried out with two-dimensional spectra (see also Supporting

Information).

Compounds 3a,b. A mixture of N,N-dimethylnaphthalen-1-amine

1 (2.44 g, 14.25 mmol) and furan-2[5H]-one 2 (80 mg, 0.95 mmol) was

irradiated for 6 h. Compounds 3a,b were isolated as a 9:1 mixture of

regioisomers. Yield: 215 mg (89%).¹H NMR (500 MHz, CDCl₃) δ 2.42

(dq (virt), J = 12.9/8.0 Hz, 1H, maj), 2.42 (m, 1H, min), 2.80 (m, 1H,

min), 2.82 (dddd, J = 4.8/7.1/9.0/12.9 Hz, 1H, maj), 2.89 (s, 6H, maj),

2.89 (s, 6H, min), 4.44 (m, 1H, maj), 4.48 (ddt, J = 4.8/8.0/9.0 Hz, 2H

maj), 4.49 (m, 2H, min), 7.05 (d, J = 7.8 Hz, 1H, maj), 7.13 (d, J = 7.5 Hz,

1H, min), 7.30 (d, J = 7.8 Hz, 1H, maj), 7.38 (d, J = 6.9 Hz, 1H, min),

7.47 (dd, J = 7.5/8.2 Hz, 1H, min), 7.47 (dd, J = 6.9/8.5 Hz, 1H, min),

7.53 (m, 2H, maj), 7.86 (m, 1H, maj), 8.28 (d, J = 8.5, 1H, min), 8.33 (m,

1H, maj); ¹³C NMR (125 MHz, CDCl₃) δ 31.5 (maj), 31.6 (min), 42.6

(maj), 43.2 (min), 45.2 (maj), 45.3 (min), 66.7 (maj), 113.6 (maj),

114.1 (min), 117.7 (min), 123.4 (maj), 124.5 (min), 124.6 (min), 125.1

(min), 125.1 (maj), 125.2 (maj), 125.3 (maj), 126.3 (maj), 126.4 (min),

127.4 (maj), 129.3 (maj), 129.5 (min), 132.4 (maj), 132.6 (min), 133.4

(min), 150.9 (maj), 151.8 (min), 177.9 (min), 178.1 (maj); IR (film) ν

2940, 1771, 1582 cm^ꢀ1. HRSM (ESI + H): m/z calcd for C₁₆H₁₈NO₂

256.1338, found 256.1331 [M + H]⁺. Anal. Calcd for C₁₆H₁₇NO₂

(255.31): C 75.27, H 6.71, N 5.49. Found: C 74.86, H 6.70, N 5.31.

Compounds 7a,b. A mixture of 4-deutero-N,N-D₆-dimethyl-

naphthalen-1-amine 5 (2.54 g, 14.25 mmol) and furan-2[5H]-one 2

(80 mg, 0.95 mmol) was irradiated for 6 h. Compounds 7a,b were

isolated as a 10:1 mixture of regioisomers. Yield: 224 mg (90%).¹H

NMR (500 MHz, CDCl₃) δ 2.39ꢀ259 (m, 1H, maj), 2.79ꢀ2.86 (m,

1H, maj), 4.47 (m, 1H, maj), 4.47 (m, 2H, maj), 7.03 (d, J = 7.7 Hz, 1H,

maj), 7.11 (d, J = 7.5 Hz, min), 7.30 (d, J = 7.7 Hz, 1H, maj), 7.37 (d, J =

6.9 Hz, 1H, min), 7.45 (m, 1H, min), 7.46 (m, 1H, min), 7.53 (m, 1H,

maj), 7.54 (m, 1H, maj), 7.86 (d, J = 8.6 Hz, 1H, maj), 8.27 (d, J = 8.5 Hz,

1H, min), 8.32 (d, J = 9.0 Hz, 1H, maj); ¹³C NMR (125 MHz, CDCl₃) δ

31.7 (maj), 31.8 (min), 42.7 (min), 42.8 (maj), 42.7ꢀ44.9 (sep, J = 20.1

Hz, maj), 66.8 (min), 66.9 (maj), 113.6 (maj), 114.1 (min), 123.4 (maj),

124.6 (min), 124.7 (min), 125.2 (maj), 125.3 (maj), 125.4 (maj), 126.4

(maj), 127.3 (maj), 129.5 (maj), 129.7 (min), 132.5 (maj), 132.6 (min),

133.4 (min), 151.1 (maj), 178.2 (maj); IR (KBr) ν 2912, 1761,

1581 cm^ꢀ1. HRSM (ESI + H): m/z calcd for C₁₆H₁₂D₆NO₂

262.1714, found 262.1704 [M + H]⁺.

’ EXPERIMENTAL SECTION

NMR spectra were recorded at frequencies of 250 MHz for ¹H and 62

MHz for ¹³C or 500 MHz for ¹H and 125 MHz for ¹³C. Chemical shifts

are given in ppm relative to TMS using residual solvent signals as

secondary references. UV Irradiations have been performed with

Rayonet reactors at λ = 350 nm. The reaction mixture was irradiated

in pyrex tubes (ϕ = 0.9 cm). Preparative chromatography was carried out

with silica gel 60A. TLC was carried out with Kieselgel 60F254 plates

form Merck.

Synthesis of 4-Deutero-N,N-dimethylnaphthalen-1-amine 4

At ꢀ40 °C and under argon atmosphere, a solution of 4-bromo-N,N-

dimethylnaphthalen-1-amine⁸⁷(10 g, 40 mmol) in ether (140 mL) was

added to a solution of n-butyllithium in hexane (48 mL, 1.6 M). The

resulting mixture was stirred for 1 h. The color changed from red to

brown. Deuterium oxide (8.6 mL) was then added. After 3 h at ꢀ30 °C

the reaction mixture was additionally stirred overnight at room tem-

perature. Water (10 mL) was added, and the mixture was extracted three

times with ether (20 mL). The organic phases were dried with MgSO₄.

After evaporation of the solvent, the residue was distilled. Yield: 6.84

(99%). ¹H NMR (500 MHz, CDCl₃) δ 2.92 (s, 6H), 7.09 (d, J = 7.4 Hz,

1H), 7.41 (d, J = 7.4 Hz, 1H), 7.46ꢀ7.52 (m, 2H), 7.84 (m, 1H), 8.26

(m, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 45.3, 114.0, 122.6 (t, J = 24.5

Hz), 124.2, 125.2, 125.7, 125.8, 128.4, 128.9, 134.9, 150.9; IR (ﬁlm) ν

2939, 1575 cm^ꢀ1. HRSM (ESI + H): m/z calcd for C₁₂H₁₃DN

173.1189, found 173.1182 [M + H]⁺.

Synthesis of 4-Deutero-N,N-bis(trideuteromethyl)-

naphthalen-1-amine5

Compounds 8a,b. A mixture of N,N-dimethylnaphthalen-1-amine

1 (2.44 g, 14.25 mmol) and furan-2[5H]-one 2 (80 mg, 0.95 mmol) was

irradiated for 6 h. Deuteriumoxide (0.375 mL) was used instead of water.

Compounds 8a,b were isolated as a 10:1 mixture of regioisomers. Yield:

At ꢀ40 °C and under argon atmosphere, a solution of 4-bromo-N,N-

dimethylnaphthalen-1-amine (19.9 g, 77.6 mmol) in ether (300 mL) was

added to a solution of n-butyllithium in hexane (93.5 mL, 1.6 M). The

resulting mixture was stirred for 2 h. The color changed from red to

1

224 mg (87%). Incorporation of 1 deuterium >90%. H NMR (500

7113

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

MHz, CDCl₃) δ 2.74 (m, 1H, maj), 2.91 (s, 6H, maj), 4.19 (m, 3H, min),

4.38ꢀ4.46 (m, 3H, maj), 7.08 (d, J = 7.7 Hz, 1H, maj), 7.16 (d, J = 7.1

Hz, 1H, min), 7.34 (d, J = 7.7 Hz, 1H, maj), 7.42 (d, J = 6.8 Hz, 1H, min),

7.55ꢀ7.59 (m, 2H, maj), 7.91 (m, 1H, maj), 8.40 (m, 1H, maj); ¹³C

NMR (125 MHz, CDCl₃) δ 30.76-31.07 (t, J = 19.7 Hz, maj), 42.3

(maj), 42.9 (min), 44.9 (maj), 45.1 (min), 60.1 (min), 66.4 (maj), 113.4

(maj), 114.0 (min), 117.5 (min), 123.3 (maj), 124.2 (min), 124.2 (min),

124.7 (min), 124.9 (maj), 124.9 (maj), 125.1 (maj), 126.3 (min), 126.2

(min), 127.3 (maj), 129.1 (maj), 129.2 (min), 132.2 (maj), 132.5 (min),

133.3 (min), 150.7 (maj), 151.8 (min), 178.0 (maj), 178.2 (min); IR

(film) ν 2940, 1771, 1582 cm^ꢀ1. HRSM (ESI + H): m/z calcd for

C₁₆H₁₇DNO₂257.1336, found 257.1333 [M + H]⁺.

Compound 10. A mixture of N,N-dimethylnaphthalen-1-amine 1

(2.44 g, 14.25 mmol) and 3-methylfuran-2[5H]-one 2 (93.2 mg, 0.95

mmol) was irradiated for 15 h. the conversion attained 62%. Compound

10 was isolated with a yield of 90 mg (35%, selectivity: 57%). ¹H NMR

(500 MHz, CDCl₃) δ 1.89 (s, 3H), 2.41 (ddd, J = 6.7/8.2/13.1 Hz, 1H),

2.89 (s, 6H), 3.09 (ddd, J = 5.8/7.4/13.1 Hz, 1H), 4.30 (ddd, J = 6.7/7.4/

13.9 Hz, 1H), 4.42 (ddd, J = 5.8/8.2/13.9 Hz, 1H), 7.00 (d, J = 8.0 Hz,

1H), 7.40 (d, J = 8.0 Hz, 1H), 7.50 (m, 1H), 7.51 (m, 1H), 7.91 (m, 1H),

8.37 (m, 1H); ¹³C NMR (125 MHz, CDCl₃) δ 24.5, 38.2, 45.3, 47.8,

65.8, 113.2, 124.7, 124.8, 125.2, 125.9, 125.9, 125.9, 130.3, 131.2, 151.3,

181.4; IR (film) ν 2939, 1771, 1585 cm^ꢀ1. HRSM (ESI + H): m/z calcd

for C₁₇H₂₀NO₂270.1494, found 270.1490 [M + H]⁺.

chromatography. A first fraction of 143 mg (25%) contained compounds

a 10/1 mixture of the regioisomers 14a,b. A second fraction of 60 mg

(10%) contained a 10/1 mixture of regioisomers 16a,b. Thus the

diastereoisomers were separated.

Compounds 14a,b. ¹H NMR (500 MHz, CDCl₃) δ 1.31 (t, J = 7.0

Hz, 3H, maj), 2.55 (m, 1H, maj), 2.74, (dd, J = 9.1/13.1 Hz, 1H), 2.88 (s,

6H, maj), 3.68 (dq J = 9.0/7.0 Hz, 1H, maj), 3.96 (dq J = 9.0/7.0 Hz, 1H,

maj), 4.68 (t (virt), J = 9.7 Hz, 1H, maj), 5.65 (d, J = 5.4 Hz, 1H, maj),

7.05 (d, J = 7.7 Hz, 1H, maj), 7.12 (d, J = 7.3 Hz, 1H, min), 7.31 (d, J =

7.7 Hz, 1H, maj), 7.38 (d, J = 6.9 Hz, 1H, min), 7.44ꢀ7.48 (m, 2H, min),

7.51ꢀ7.53 (m, 2H, maj), 7.56 (d, J = 8.8 Hz, 1H, min), 7.85 (m, 1H,

maj), 8.28 (d, J = 8.4 Hz, 1H, min), 8.33 (m, 1H, maj); ¹³C NMR (125

MHz, CDCl₃) δ 15.1 (maj), 38.5 (maj), 38.6 (min), 41.6 (maj), 42.1

(min), 45.3 (maj), 45.4 (min), 65.3 (maj), 102.1 (maj), 113.8 (maj),

114.3 (min), 117.8 (min), 123.4 (maj), 124.6 (min), 124.9 (min), 125.2

(maj), 125.3 (maj), 125.8 (maj), 126.5 (maj), 127.5 (maj), 129.4 (maj),

132.6 (maj), 132.8 (min), 133.4 (min), 151.0 (maj), 151.8 (min), 177.6

(maj); IR (film) ν 2938, 1778, 1583 cm^ꢀ1. HRSM (ESI + H): m/z calcd

for C₁₈H₂₂NO₃300.1600, found 300.1591 [M + H]⁺.

Compounds 16a,b. ¹H NMR (500 MHz, CDCl₃) δ 1.28 (t, J = 7.0

Hz, 3H, maj), 2.34 (m, 1H, maj), 2.88 (m, 6H, maj), 3.02 (m, 1H, maj),

3.70 (dq J = 9.0/7.0 Hz, 1H, maj), 4.00 (dq J = 9.0/7.0 Hz, 1H, maj), 4.49

(dd, J = 8.3/10.0 Hz, 1H, maj), 4.54 (dd, J = 8.3/10.2 Hz, 1H, min), 5.67

(t (virt), J = 4.9/5.3 Hz, 1H, maj), 7.05 (d, J = 7.8 Hz, 1H, maj), 7.12 (d,

J = 7.4 Hz, 1H, min), 7.41 (d, J = 7.8 Hz, 1H, maj), 7.41ꢀ7.47 (m, 3H,

min), 7.52 (m, 2H, maj), 7.55 (d, J = 9.3 Hz, 1H, min), 7.87 (m, 1H,

maj), 8.27 (d, J = 7.5 Hz, 1H, min), 8.33 (m, 1H, maj); ¹³C NMR (125

MHz, CDCl₃) δ 15.1 (maj), 37.4 (maj), 37.6 (min), 42.7 (maj), 43.3

(min), 45.3 (maj), 45.4 (min), 66.1 (maj), 103.1 (maj), 104.5 (min),

113.8 (maj), 114.2 (min), 117.9 (min), 123.5 (maj), 124.7 (min), 124.8

(min), 125.1 (maj), 125.2 (maj), 126.0 (maj), 126.4 (maj), 127.8 (maj),

129.4 (maj), 132.5 (maj), 151.0 (maj), 151.9 (min), 176.4 (min), 177.5

(maj); IR (film) ν 2938, 1773, 1582 cm^ꢀ1. HRSM (ESI + H): m/z calcd

for C₁₈H₂₂NO₃300.1600, found 300.1595 [M + H]⁺.

Transformation of 5-Substituted Furanone 11. A mixture of

N,N-dimethylnaphthalen-1-amine 1 (4.88 g, 28.5 mmol) and 5-methyl-

furan-2[5H]-one 11 (186 mg, 1.9 mmol) was irradiated for 6 h. After

evaporation, the product mixture was separated by column chromatog-

raphy. A first fraction of 250 mg (45%) contained compounds a 11/1

mixture of the regioisomers 13a,b. A second fraction of 68 mg (13%)

contained a 10/1 mixture of regioisomers 15a,b. Thus the diastereoi-

somers were separated.

Compounds 13a,b. ¹H NMR (500 MHz, CDCl₃) δ 1.48 (d, J =

6.2 Hz, 1H, maj), 2.42ꢀ2.48 (m, 2H, maj), 2.88 (s, 6H, maj), 2.89 (s, 6H,

min), 4.55 (dd, J = 6.0/8.5 Hz, 1H, maj), 4.6 (dd, J = 6.6/8.0 Hz, 1H,

min), 4.77 (m, 1H, maj), 7.02 (d, J = 7.8 Hz, 1H, maj), 7.12 (d, J = 7.4 Hz,

1H, min), 7.26 (d, J = 7.8 Hz, 1H, maj), 7.34 (d, J = 6.9 Hz, 1H, min),

7.42ꢀ7.48 (m, 2H, min), 7.51ꢀ7.55 (m, 2H, maj), 7.84 (m, 1H, maj),

8.26 (d, J = 8.5 Hz, 1H, min), 8.32 (m, 1H, maj); ¹³C NMR (125 MHz,

CDCl₃) δ 21.0 (maj), 38.8 (maj), 38.9 (min), 43.8 (maj), 44.4 (min),

45.3 (2x, maj), 44.5 (2x, min), 75.7 (maj), 113.6 (maj), 114.3 (min),

117.9 (min), 123.5 (maj), 124.6 (min), 124.7 (maj), 125.3 (maj), 126.5

(maj), 126.6 (min), 127.4 (maj), 129.6 (maj), 132.4 (maj), 132.5 (min),

133.8 (min), 151.0 (maj), 177.9 (min), 178.1 (maj); IR (film) ν 2938,

1771, 1582 cm^ꢀ1. HRSM (ESI + H): m/z calcd for C₁₇H₂₀NO₂

270.1494, found 270.1491 [M + H]⁺.

Compounds 19a,b. A mixture of N,N-dimethylnaphthalen-1-

amine 1 (2.44 g, 14.25 mmol) and methylcrotonate 17 (95 mg, 0.95

mmol) was irradiated for 8 h. Compounds 8a,b were isolated as a 9:1

1

mixture of regioisomers. Yield: 115 mg (60%). H NMR (500 MHz,

CDCl₃) δ 1.00 (t, J = 7.3 Hz, 3H, maj), 1.00 (3H, min), 1.96 (dp, J = 6.6/

7.3 Hz, 1H, maj), 1.96 (1H, min), 2.29 (dp, J = 8.2/7.3 Hz, 1H, maj),

2.29 (1H, min), 2.90 (s, 6H, maj), 2.90 (6H, min), 3.66 (s, 3H, maj), 4.25

(dd, J = 6.7/8.2 Hz, 1H, maj), 4.31 (dd, J = 6.7/8.2 Hz, 1H, min), 7.08 (d,

J = 7.8 Hz, 1H, maj), 7.12 (d, J = 7.4 Hz, 1H, min), 7.43 (d, J = 7.8 Hz,

1H, maj), 7.47 (dd, J = 7.4/8.5 Hz, 1H, min), 7.47ꢀ7.49 (m, 1H, min),

7.51 (m, 1H, min), 7.52 (m, 1H, maj), 7.54 (m, 1H, maj), 7.83 (d, J = 8.5

Hz, 1H, min), 8.13 (dd, J = 1.3/7.8 Hz, 1H, maj), 8.25 (d, J = 8.1 Hz, 1H,

min), 8.33 (dd, J = 1.6/7.8 Hz, 1H, min); ¹³C NMR (125 MHz, CDCl₃)

δ 12.7 (maj), 12.7 (min), 26.5 (maj), 26.6 (min), 45.4 (maj), 45.5 (min),

48.4 (maj), 48.9 (min), 52.1 (maj), 113.9 (maj), 114.0 (min), 118.1

(min), 123.6 (maj), 123.8 (min), 124.8 (min), 124.9 (min), 124.9 (maj),

125.0 (maj), 125.1 (maj), 126.2 (min), 126.2 (maj), 129.3 (maj), 129.6

(min), 130.0 (maj), 132.9 (maj), 133.1 (min), 135.8 (min), 150.3 (maj),

151.8 (maj), 175.0 (min), 175.2 (maj); IR (film) ν 2948, 1734, 1583,

1169 cm^ꢀ1. HRSM (ESI + Na): m/z calcd for C₁₇H₂₁NO₂Na 294.1470,

found 294.1475 [M + Na]⁺.

Compounds 15a,b. ¹H NMR (500 MHz, CDCl₃) δ 1.53 (d, J =

6.1 Hz, 1H, maj), 2.08 (ddd, J = 5/6/11.5 Hz, 1H, maj), 2.88 (s, 6H, maj,

min), 4.52 (dd, J = 9.1/11.8 Hz, 1H, maj), 4.58 (m, 1H), 4.74 (m, 1H),

7.06 (d, J = 7.7 Hz, 1H), 7.11 (d, J = 7.3 Hz, 1H, min), 7.36 (d, J = 7.7 Hz,

1H, maj), 7.43ꢀ7.47 (m, 3H, min), 7.51ꢀ7.53 (m, 2H, maj), 7.56 (d, J =

9.1 Hz, 1H, min), 7.85 (m, 1H, maj), 8.27 (d, J = 8.3 Hz), 8.33 (m, 1H);

¹³C NMR (125 MHz, CDCl₃) δ 31.2 (maj), 39.8 (maj), 39.9 (min), 44.8

(maj), 45.3 (2x, maj), 45.4 (2x, min), 75.3 (maj), 113.8 (maj), 114.2

(min), 117.7 (min), 123.4 (maj), 124.5 (min), 124.6 (min), 125.1 (maj),

125.3 (maj), 125.9 (maj), 126.3 (maj), 126.4 (min), 127.5 (maj), 129.4

(maj), 129.6 (min), 132.6 (maj), 132.8 (min), 133.5 (min), 152.0 maj),

151.9 (min), 177.3 (min), 177.5 (maj); IR (film) ν 2936, 1764,

1582 cm^ꢀ1. HRSM (ESI + H): m/z calcd for C₁₇H₂₀NO₂270.1494,

found 270.1497 [M + H]⁺.

Compounds 20a,b and 21. A mixture of N,N-dimethylnaphtha-

len-1-amine 1 (2.44 g, 14.25 mmol) and dimethylfumarate 18 (137 mg,

0.95 mmol) was irradiated for 8 h. Compounds 20a,b and 21 were

1

isolated as a 11:1:2.5 mixture. Yield: 205 mg (69%). H NMR (500

MHz, CDCl₃) δ 2.74 (dd, J = 4.3/17.1 Hz, 1H, maj), 2.74 (m, 1H, min),

2.88 (s, 6H, maj), 2.88 (s, 6H, min), 3.05 (s, 3H, 21), 3.27 (dd, J = 11.5/

13.4 Hz, 21), 3.34 (dd, J = 10.4/17.1 Hz, 1H, maj), 3.34 (m, 1H, min),

3.60 (dd, J = 3.6/13.4 Hz, 1H, 21), 3.68 (s, 3H, maj), 3.68 (s, 3H, min),

3.71 (s, 3H, maj), 3.71 (s, 3H, min), 3.79 (s, 3H, 21), 3.82 (s, 3H, min),

Transformation of 5-Substituted Furanone 12. A mixture of

N,N-dimethylnaphthalen-1-amine 1 (4.88 g, 28.5 mmol) and 5-ethox-

yfuran-2[5H]-one 12 (243 mg, 1.9 mmol) was irradiated for 6 h.

After evaporation, the product mixture was separated by column

7114

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

4.35 (d, J = 10.3 Hz, 1H, 21), 4.87 (dd, J = 4.3/10.4 Hz, 1H, maj), 4.93

(dd, J = 4.4/10.5 Hz, 1H, min), 7.02 (d, J = 7.8 Hz, 1H, maj), 7.12 (d, J =

7.4 Hz, 1H, min), 7.30 (d, J = 7.8 Hz, 1H, maj), 7.37 (m, 1H, min), 7.38

(m, 1H, 21), 7.44 (m, 1H, min), 7.45 (m, 1H, 21), 7.48 (m, 1H, min),

7.49 (m, 2H, 21), 7.52 (m, 1H, maj), 7.54 (m, 1H, maj), 7.77 (d, J = 7.4

Hz, 1H, 21), 7.77 (m, 1H, min), 8.08 (dd, J = 1.0/8.1 Hz, maj), 8.17 (d,

J = 8.3 Hz, 1H, 21), 8.25 (d, J = 8.3 Hz, 1H, min), 8.31 (dd, J = 1.4/8.0

Hz, 1H, maj); ¹³C NMR (125 MHz, CDCl₃) δ 36.9 (21), 37.6 (maj),

37.6 (min), 42.8 (maj), 43.2 (min), 44.2 (21), 45.3 (maj), 45.3 (min),

46.2 (21), 52.0 (maj), 52.3 (21), 52.4 (21), 52.5 (maj), 52.7 (21), 113.7

(maj), 114.3 (min), 117.8 (min), 120.8 (21), 123.4 (maj), 123.7 (21),

124.0 (21), 124.5 (min), 125.2 (maj), 125.6 (21), 125.8 (21), 126.0

(21), 126.6 (maj), 128.4 (maj), 128.5 (21), 129.4 (maj), 129.7 (min),

132.3 (maj), 132.5 (min), 133.9 (21), 144.2 (21), 150.8 (min), 150.9

(maj), 172.4 (min), 172.5 (maj), 173.6 (21), 174.1 (21), 174.2 (min),

174.3 (maj); IR (film) ν 2951, 1733, 1582, 1160 cm^ꢀ1. HRSM (ESI +

Na): m/z calcd for C₁₈H₂₁NO₄Na 338.1368, found 338.1367 [M +

Na]⁺(maj, min).

Compound 23. A mixture of N,N-dimethylnaphthalen-2-amine 22

(2.44 g, 14.25 mmol) and furan-2[5H]-one 2 (80 mg, 0.95 mmol) was

irradiated for 15 h. Compound 23 was isolated as with a yield of 205 mg

(85%). Due to conformational restrictions, NMR spectra recorded in

CDCl₃at room temperature had domains with low resolution. ¹H NMR

(500 MHz, DMSO-d₆, 80 °C) δ 2.38ꢀ2.48 (m, 2H), 2.65 (s, 6H), 4.45

(dd, J = 8.8/16.9 Hz, 1H), 4.57 (dt (virt), J = 3.2/8.8 Hz, 1H), 4.94 (t

(virt), J = 9.8 Hz, 1H), 7.42ꢀ7.58 (m, 3H), 7.89 (m, 3H); ¹³C NMR

(125 MHz, DMSO-d₆, 80 °C) δ 29.2, 37.6, 44.9, 65.7, 120.6, 123.3,

124.2, 125.8, 128.1, 128.6, 131.3 (2ꢁ), 131.4, 150.1, 177.2; IR (KBr) ν

2936, 1761, 1451, 1183 cm^ꢀ1. HRSM (ESI + H): m/z calcd for

C₁₆H₁₈NO₂256.1338, found 256.1335 [M + H]⁺.

8.32 (m, 1H); ¹³C NMR (62.5 MHz, CDCl₃) δ 15.6, 21.0, 22.2, 22.9,

25.2, 31.3, 34.2, 37.4, 39.6, 42.9, 45.2, 47.7, 77.4, 99.2, 113.4, 123.5,

125.0, 125.1, 125.9, 126.2, 127.9, 129.4, 132.4, 150.9, 176.6.

Physicochemical Studies. The solvent acetonitrile (Baker,

HPLC grade) was dried over molecular sieve (3 Å), redistilled, and

stored under argon atmosphere. All samples to be measured contained

2.2 ꢁ 10^ꢀ5M N,N-dimethyl-1-naphthylamine 1 and were prepared and

kept under argon atmosphere. For the SternꢀVolmer quenching series

the liquid quencher 2[5H]-furanone 2 was directly added into the

cuvette with the help of a Hamilton syringe in stepwise concentrations

up to 0.06 M. When the influence of water on the reaction was studied,

the samples were prepared in the same way, except that 1% of bidistilled

water was deliberately added before measurement. Absorption spectra

were recorded on a Shimadzu UV-3101-PC UVꢀvisꢀNIR spectro-

photometer. Steady state fluorescence measurements (excitation

312 nm) were carried out using a Jobin Yvon Fluoromax-2 spectro-

fluorimeter, while the corresponding time-resolved fluorescence mea-

surements were performed on a custom-built LED-based modulation

fluorimeter (excitation LED 340 nm, cutoff filter GG 400) that has been

described elsewhere.⁸⁸During all fluorescence experiments the sample

cuvette was thermostatted to 298 K (25 °C). Fluorescence quantum

yields were determined against 2.2 ꢁ 10^ꢀ5M quinine hemisulfate in 0.5

M H₂SO₄(excitation 347.5 nm, Φ = 0.546).

Cyclic Voltammetry of Furanones 2 and 25. Cyclic voltam-

metry was carried out with an Autolab PGSTAT12 potentiostat from

ECO Chemie coupled to an electrochemical cell with three electrodes.

A platinum disk was used as working electrode with a Pt wire as

counter. Ag/AgNO₃was used as reference electrode. Solutions of

the furanone derivatives 2 and 25 or N,N-dimethylnaphthylamine 1

(10^ꢀ3mol L^ꢀ1) in acetonitrile containing Bu₄NPF₆(0.1 mol L^ꢀ1

)

Transformation of 5-Menthyloxyfuran-2[5H]-one 25

Using Heterogeneous Photocatalysis. Photochemical transfor-

mation of the N,N-dimethylnaphthalen-1-amine 1 with 5-menthylox-

yfuran-2[5H]-one 25 under heterogeneous photocatalytic conditions. A

suspension of menthyloxyfuranone 25 (250 mg, 1.05 mmol), N,N-

dimethylnaphthalen-1-amine 1 (8.55 mg, 53 mmol), and TiO₂(99%

anatase purchased from ACROS) (16 mg, 0.2 mmol) in acetonitrile

(40 mL) was filled in pyrex tubes (ϕ = 2 cm) and purged with argon for

30 min before being irradiated at λ = 350 nm (Rayonet). During

irradiation, the suspension was stirred with a magnetic stirring bar. After

7 h of irradiation and filtration over Celite, the solvent and the amine

excess were evaporated. The residue was subjected to column chroma-

tography (eluent, ethyl acetate/petroleum ether, 1:5). A first fraction of

136 mg (32%, selectivity 39%) contained 26; [R]²¹_D= 29.4 (c 0.320 in

CH₂Cl₂). A second fraction contained a mixture of compounds 25, 27,

and the reduction product 28. The proportion of different constituents

have been measured with a scan rate of 100 mV s^ꢀ1. Fc⁺/Fc was used as

red

internal reference. Furan-2[5H]-one 2: E_p= ꢀ2.75 V. 5-Menthy-

red

loxyfuran-2[5H]-one 25: E_p= ꢀ2.52 V. N,N-Dimethylnaphthyla-

mine 1: E_p^ox= +0.39 V.

Quantum Chemical Calculations. Quantum chemical calcula-

tions for the radical cation I were performed using HyperChem 5.11

Prof: Geometry optimization was carried out with 3-21G to C_S

symmetry. Calculations on the optimized structure were carried out

with UHF/6-31 G**.

’ ASSOCIATED CONTENT

S

Supporting Information. Tables with two dimentional

b

NMR data of compounds 10, 19a, 19b, 20a, 20b, 21, and 26;

NOE of compound 26; copies of ¹H NMR and ¹³C NMR spectra

and cyclic voltametry of N,N-dimethylnaphthylamine 1, fura-

none 2, and 5-menthyloxyfuranone 25; atom coordinates of the

radical cation I. This material is available free of charge via the

Internet at http://pubs.acs.org.

1

was determined by H NMR spectroscopy. Yield of 27: 43 mg (10%,

selectivity 12%). Yield of 28:³⁹15 mg (6%, selectivity 7%).

Compound 26. ¹H NMR (250 MHz, CDCl₃) δ 0.85 (d, J = 6.8

Hz, 3H), 0.94 (d, J = 6.8 Hz, 6H), 0.76ꢀ1.09 (m, 3H), 1.18ꢀ1.50 (m,

2H), 1.61ꢀ1.75 (m, 2H), 2.10ꢀ2.30 (m, 2H), 2.56 (ddd, J = 13.2/

10.7/5.4 Hz, 1H), 2.73 (dd, J = 13.2/8.8 Hz, 1H), 2.90 (s, 6H), 3.68

(dt, J = 10.7/4.1 Hz, 1H), 7.34 (d, J = 7.8 Hz, 1H), 7.41ꢀ7.60 (m, 2H),

7.86 (m, 1H), 8.34 (m, 1H); ¹³C NMR (62.5 MHz, CDCl₃) δ 15.6,

21.0, 22.2, 23.0, 25.6, 31.3, 34.3, 38.7, 39.8, 41.7, 45.1, 47.8, 76.6, 98.3,

113.6, 123.2, 125.0, 125.2, 125.8, 126.2, 127.3, 129.3, 132.4, 151.0,

177.2; IR (KBr) ν 2959, 1789, 1455, 1199 cm^ꢀ1; MS (EI) m/z (%) 409

(26) [M]⁺, 226 (100), 197 (38), 182 (12), 153 (14). Anal. Calcd for

C₂₆H₃₅NO₃(409.56): C 76.25, H 8.61, N 3.42. Found: C 76.78, H

9.11, N 3.42.

’ AUTHOR INFORMATION

Corresponding Author

*E-mail: norbert.hoﬀmann@univ-reims.fr.

’ ACKNOWLEDGMENT

Compound 27. ¹H NMR (250 MHz, CDCl₃) (only signals that are

attributable are reported) δ 2.86 (s, 6H), 3.52 (dt, J = 10.6/4.2 Hz, 1H),

4.47 (dd, J = 10.5/7.2 Hz, 1H), 5.90 (dd, J = 6.1/4.0 Hz, 1H), 7.02 (d, J =

7.8 Hz, 1H), 7.39 (d, J = 7.6 Hz, 1H), 7.47ꢀ7.58 (m, 2H), 7.86 (m, 1H),

We thank the French Ministꢂere de l’Enseignement supꢀerieur

et de la Recherche, the Rꢀegion Champagne-Ardenne, Syngenta

Crop Protection Muenchwilen AG, and ADEME/AGRICE

(Project 0601C0022) for ﬁnancial support.

7115

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

’ REFERENCES

(18) (a) Pandey, G. In Organic Photochemistry; Ramamurthy, V.,

Schanze, K., Eds.; Marcel Dekker: New York, 1997; pp 245ꢀ293. (b)

Mattay, J. Synthesis 1989, 233–252.

(1) (a) CRC Handbook of Organic Photochemistry and Photobiology,

2nd ed.; Horspool, W., Lenci, F., Eds.; CRC Press: Boca Raton, FL,

2004. (b) Klꢀan, P.; Wirz, J. Photochemistry of Organic Compounds; Wiley:

Chichester, 2009. (c) Turro, N. J.; Ramamurthy, V.; Scaiano, J. C.

Modern Molecular Photochemistry of Organic Molecules; University

Science Books: Sausalito, 2010. (d) Synthetic Organic Photochemistry;

Griesbeck, A. G., Mattay, J., Eds.; Marcel Dekker: New York, 2005.

(e) Handbook of Synthetic Photochemistry; Albini, A., Fagnoni, M., Eds;

Wiley-VCH: Weinheim, 2010. (f) Hoﬀmann, N. Chem. Rev. 2008,

108, 1052–1103. (g) Hoﬀmann, N.; Gramin, J.-C.; Bouas-Laurent, H.

Actual. Chim. 2008, 317, 6–13. (h) Bach, T.; Hehn, J. P. Angew. Chem.,

Int. Ed. 2011, 50, 1000–1045.

(2) (a) Ciamician, G. Science 1912, 36, 385–394. (b) Esser, P.;

Pohlmann, B.; Scharf, H.-D. Angew. Chem., Int. Ed. Engl. 1994,

33, 2009–2023. (c) Protti, S.; Dondi, D.; Fagnoni, M.; Albini, A. Pure

Appl. Chem. 2007, 79, 1929–1938. (d) Oelgem€oller, M.; Jung, C.;

Mattay, J. Pure Appl. Chem. 2007, 79, 1939–1947. (e) Hoﬀmann, N.

Pure Appl. Chem. 2007, 79, 1949–1958.

(3) (a) Turro, N. J. Angew. Chem., Int. Ed. Engl. 1986, 25, 882–892.

See also:(b) Olivucci, M.; Santoro, F. Angew. Chem., Int. Ed. 2008,

47, 6322–6325.

(4) (a) Rehm, D.; Weller, A. Ber. Bunsen-Ges. Phys. Chem. 1969,

73, 834–839. (b) Rehm, D.; Weller, A. Isr. J. Chem. 1970, 8, 259–271.

(c) Weller, A. Z. Phys. Chem. (M€unchen) 1982, 130, 129–138. (d) Weller,

A. Z. Phys. Chem. (M€unchen) 1982, 133, 93–98.

(5) (a) Kavarnos, G. J. Fundamentals of Photoinduced Electron

Transfer; VCH: New York, 1993. (b) Electron Transfer in Chemistry;

Balzani, V., Ed.; Wiley-VCH: Weinheim, 2001; Vols. 1ꢀ5. (c) Photo-

induced Electron Transfer; Fox, M. A., Chanon, M., Eds.; Elsevier:

Amsterdam, 1988.

(6) (a) Rosspeintner, A.; Kattnig, D. R.; Angulo, G.; Landgraf, S.;

Grampp, G. Chem.—Eur. J. 2008, 14, 6213–6221. (b) Rosspeintner, A.;

Kattnig, D. R.; Angulo, G.; Landgraf, S.; Grampp, G.; Cuetos, A. Chem.

—Eur. J. 2007, 13, 6474–6483.

(7) Todres, Z. V. Ion-Radical Organic Chemistry, 2nd ed.; CRC Press:

Boca Raton, 2009.

(8) (a) Marcus, R. A. Annu. Rev. Phys. Chem. 1964, 15, 155–196.

(b) Marcus, R. A. J. Chem. Phys. 1965, 44, 679–701. (c) Marcus, R. A.;

Sutin, N. Biochim. Biophys. Acta 1985, 811, 265–322. (d) Sutin, N. Acc.

Chem. Res. 1982, 15, 275–282.

(9) Hoﬀmann, N.; Bertrand, S.; Marinkoviꢀc, S.; Pesch, J. Pure Appl.

Chem. 2006, 78, 2227–2246.

(10) Griesbeck, A. G.; Hoﬀmann, N.; Warzecha, K.-D. Acc. Chem.

Res. 2007, 40, 128–140.

(11) Hoﬀmann, N. J. Photochem. Photobiol. C: Photochem. Rev. 2008,

9, 43–60.

(12) Fagnoni, M.; Dondi, D.; Ravelli, D.; Albini, A. Chem. Rev. 2007,

107, 2725–2756.

(13) (a) Marinkoviꢀc, S.; Hoﬀmann, N. Chem. Commun.

2001, 1576–1578. (b) Marinkoviꢀc, S.; Hoﬀmann, N. Int. J. Photoenergy

2003, 383, 451–455.

(14) (a) Harakat, D.; Pesch, J.; Marinkoviꢀc, S.; Hoﬀmann, N. Org.

Biomol. Chem. 2006, 4, 1202–1205. (b) Gassama, A.; Ernenwein, C.;

Hoﬀmann, N. ChemSusChem 2009, 2, 1130–1137.

(19) (a) Yoon, U. C.; Mariano, P. S. Acc. Chem. Res. 1992,

25, 233–240. (b) Yoon, U. C.; Mariano, P. S.; Givens, R. S.; Atwater,

B. W., III Adv. Electron Transfer Chem. 1994, 4, 117–205.

(20) Cossy, J. In Radicals in Organic Synthesis; Renaud, P., Sibi, M. P.,

Eds.; Wiley-VCH: Weinheim, 2001; Vol. 1, pp 229ꢀ249.

(21) (a) Dichiarante, V.; Fagnoni, M. Synlett 2008, 787–800.

(b) Fagnoni, M.; Albini, A. Acc. Chem. Res. 2005, 38, 713–721.

(c) Dichiarante, V.; Fagnoni, M.; Albini, A. J. Org. Chem. 2010,

75, 1271–1276. (d) Protti, S.; Dondi, D.; Fagnoni, M.; Albini, A. Eur.

J. Org. Chem. 2008, 2240–2247. (e) Dichiarante, V.; Fagnoni, M.; Albini,

A. Angew. Chem., Int. Ed. 2007, 46, 6495–6498. (f) Dichiarante, V.;

Fagnoni, M.; Mella, M.; Albini, A. Chem.—Eur. J. 2006, 12, 3905–3915.

(g) Protti, S.; Fagnoni, M.; Albini, A. Angew. Chem., Int. Ed. 2005,

44, 5675–5678. See also: (h) Rossi, R. A.; Pierini, A. B.; Santiago, A. N.

Org. React. 1999, 54, 1–271.

(22) (a) Kanaoka, Y. Acc. Chem. Res. 1978, 11, 407–413.

(b) Griesbeck, A. G. Liebigs Ann. 1996, 1951–12958. (c) Yoon, U. C.;

Mariano, P. S. Acc. Chem. Res. 2001, 34, 523–532. (d) Oelgem€oller, M.;

Griesbeck, A. G. J. Photochem. Photobiol. C: Photochem. Rev. 2002,

3, 109–127. (e) McDermott, G.; Yoo, D. J.; Oelgem€oller, M. Heterocycles

2005, 65, 2221–2257.

(23) (a) Dyker, G. Angew. Chem., Int. Ed. 1999, 38, 1698–1712.

(b) Handbook of C-H Transformations; Dyker, G., Ed.; Wiley-VCH:

Weinheim, 2005; Vols. 1 and 2. (c) Ritleng, V.; Sirlin, C.; Pfeﬀer, M.

Chem. Rev. 2002, 102, 1731–1769. (d) Adv. Synth. Catal. 2003, 345,

(9ꢀ10), Special Issue: Activation of Unreactive Bonds for Organic

Synthesis. (e) Chem. Rev. 2010, 110, (2), Special Issue: Selective

Functionalization of C-H Bonds.

(24) For a discussion on the term “C-H Activation”, see: Sezen, B.;

Sames, D. In Handbook of C-H Transformations; Dyker, G., Ed.; Wiley-

VCH: Weinheim, 2005; Vol. 1, pp 3ꢀ10.

(25) In the particular context of arylations, see also: (a) Modern

Arylation Methods; Ackermann, L., Ed.; Wiley-VCH: Weinheim, 2009.

(b) Rueping, M.; Nachtsheim, B. J. Beilstein J. Org. Chem. 2010, 6, (6),

DOI:10.3762/bjoc.6.6.

(26) Stone, K. L.; Borovik, A. S. Curr. Opin. Chem. Biol. 2009,

13, 114–118 and references cited therein.

(27) (a) Little, R. D.; Masjedizadeh, M. R.; Wallquist, O.; McLoughlin,

J. I. Org. Reac. 1994, 47, 315–552. (b) Bergmann, E. D.; Ginsburg, D.;

Pappo, R. Org. Reac. 1959, 10, 179–555.

(28) (a) Ho, T.-L. Tandem Organic Reactions; John Wiley & Sons:

New York, 1992. (b) Tietze, L. F.; Brasche, G.; Gericke, K. M. Domino

Reactions in Organic Synthesis; Wiley-VCH: Weinheim, 2006. (c) Tourꢀe,

B. B.; Hall, D. G. Chem. Rev. 2009, 109, 4439–4486.

(29) Basavaiah, D.; Rao, A. J.; Satyanarayana, T. Chem. Rev. 2003,

103, 811–891.

(30) McQuaid, K. M.; Sames, D. J. Am. Chem. Soc. 2009, 131, 402–

403.

(31) Jahjah, R.; Gassama, A.; Bulach, V.; Suzuki, C.; Abe, M.;

Hoﬀmann, N.; Martinez, A.; Nuzillard, J.-M. Chem.—Eur. J. 2010,

16, 3341–3354.

(32) (a) Alibꢀes, R.; Bourdelande, J. L.; Font, J.; Gregori, A.; Parella,

T. Tetrahedron 1996, 52, 1267–1278. (b) de March, P.; Figueredo, F.;

Font, J.; Raya, J.; Alvarez-Larena, A.; Piniella, J. F. J. Org. Chem. 2003,

68, 2437–2447. (c) Paquette, L. A.; Pansegrau, P. D.; Wiedeman, P. E.;

Springer, J. P. J. Org. Chem. 1988, 53, 1461–1466. (d) Belluꢁs, D.; Kearns,

D. R.; Schaﬀner, K. Helv. Chim. Acta 1969, 52, 971–1009.

(33) See also: (a) Hoﬀmann, N.; Buschmann, H.; Raabe, G.; Scharf,

H.-D. Tetrahedron 1994, 50, 11167–11186. (b) Wiesner, K. Tetrahedron

1975, 31, 1655–1658. (c) Marini-Bettꢂolo, G.; Sahoo, S. P.; Poulton,

G. A.; Tsai, T. Y. R.; Wiesner, K. Tetrahedron 1980, 36, 719–721.

(d) Chan, C. B.; Schuster, D. I. J. Am. Chem. Soc. 1982, 104, 2928–2929.

(e) Braussaud, N.; Hoﬀmann, N.; Scharf, H.-D. Tetrahedron 1997,

53, 14701–14712. (f) Becker, D.; Nagler, M.; Sahali, Y.; Haddad, N.

J. Org. Chem. 1991, 56, 4537–4543.

(15) See also: Quiclet-Sire, B.; Zard, S. Z. Chem.—Eur. J. 2006,

12, 6002–6016.

(16) (a) Lalevꢀee, J.; Allonas, X.; Genet, S.; Fouassier, J.-P.

J. Am. Chem. Soc. 2003, 125, 9377–9380. (b) Lalevꢀee, J.; Allonas, X.;

Fouassier, J.-P. J. Phys. Chem. A 2004, 108, 4326–4224. (c) Lalevꢀee, J.;

Graﬀ, B.; Allonas, X.; Fouassier, J.-P. J. Phys. Chem. A 2007, 111,

6991–6998.

(17) (a) Moad, G.; Rizzardo, E.; Thang, S. H. Acc. Chem. Res. 2008,

41, 1133–1142. (b) Barner-Kowollik, C.; Perrier, S. J. Polym. Sci., Part A:

Polym. Chem. 2008, 46, 5715–5723. (c) Boyer, C.; Bulmus, V.; Davis,

T. P.; Ladmiral, V.; Liu, J.; Perrier, S. Chem. Rev. 2009, 109, 5402–

5436.

7116

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

(34) For physicochemical or theoretical studies, see: (a) Bonneau, R.

J. Am. Chem. Soc. 1980, 102, 3816–3822. (b) Chan, A. C.; Schuster, D. I.

J. Am. Chem. Soc. 1986, 108, 4561–4567. (c) Yamauchi, S.; Hirota, N.;

Higuchi, J. J. Phys. Chem. 1988, 92, 2129–2133. (d) Schuster, D. I.;

Dunn, D. A.; Heibel, G. E.; Brown, P. B.; Rao, J. M.; Woning, J.;

Bonneau, R. J. Am. Chem. Soc. 1991, 113, 6245–6255. (e) Reguero, M.;

Olivucci, M.; Bernardi, F.; Robb, M. A. J. Am. Chem. Soc. 1994,

116, 2103–2114. (f) Wilsey, S.; Gonzꢀalez, L.; Robb, M. A.; Houk,

K. N. J. Am. Chem. Soc. 2000, 122, 5866–5876.

(54) (a) Pandey, G. Synlett 1992, 546–552. (b) Ferroud, C.; Rool,

P.; Santamaria, J. Tetrahedron Lett. 1998, 39, 9423–9426. (c) Zhang, X.;

Jung, Y. S.; Mariano, P. S.; Fox, M. A.; Martin, P. S.; Merkert, J.

Tetrahedron Lett. 1993, 34, 5239–5242. (d) Cossy, J.; Guha, M.

Tetrahedron Lett. 1994, 35, 1715–1718. (e) Karki, S. B.; Dinnocenzo,

J. P.; Jones, J. P.; Korzekwa, K. R. J. Am. Chem. Soc. 1995,

117, 3657–3664. (f) Bietti, M.; Cuppoletti, A.; Dagostin, C.; Florea,

C.; Galli, C.; Gentili, P.; Petride, H.; Caia, C. R. Eur. J. Org. Chem.

1998, 2425–2429.

(35) (a) Taylor, R. Electrophilic Aromatic Substitution; J. Wiley &

Sons: Chichester, 1990. (b) Taylor, R. Chimia 1968, 22, 1–64.

(36) (a) Bender, C.; Liebscher, J. ARKIVOC 2009, No. vi, 111–136.

(b) Kumar, A.; Sharma, S.; Maurya, R. A. Tetrahedron Lett. 2009,

50, 5937–5940. (c) Jiang, S.; Crogan-Grundy, C.; Drewe, J.; Tseng,

B.; Cai, S. X. Bioorg. Med. Chem. Lett. 2008, 18, 5725–5728.

(d) Periasamy, M.; Kishorebabu, N.; Jayakumar, K. N. Tetrahedron Lett.

2007, 48, 1955–1958. (e) Zhao, J.-L.; Liu, L.; Zhang, H.-B.; Wu, Y.-C.;

Wang, D.; Chen, Y. J. Tetrahedron Lett. 2006, 47, 2511–2514. (f) Hapiot,

P.; Mꢀedebielle, M. J. Fluorine Chem. 2001, 107, 285–300. (g) Cheng, Y.;

Ye, H.-L.; Zhan, Y.-H.; Meth-Cohn, O. Synthesis 2001, 904–908.

(37) (a) Semenova, O. N.; Kudryavtseva, Yu. A.; Ermolenko, I. G.;

Patsenker, L. D. Russ. J. Org. Chem. 2005, 41, 1100–1101. (b) Takahashi,

H.; Kashiwa, N.; Hashimoto, Y.; Nagasawa, K. Tetrahedron Lett. 2002,

43, 2935–2938. (c) Cheng, Y.; Yang, H.-B.; Liu, B.; Meth-Cohn, O.;

Watkin, D.; Humphries, S. Synthesis 2002, 906–910. (d) Umemiya, H.;

Fukasawa, H.; Ebisawa, M.; Eyrolles, L.; Kawachi, E.; Eisenmann, G.;

Gronemeyer, H.; Hashimoto, Y.; Shudo, K.; Kageshita, H. J. Med. Chem.

1997, 40, 4222–4234.

(55) For selected examples, see: (a) Urry, W. H.; Trecker, D. J.;

Hartzler, H. D. J. Org. Chem. 1964, 29, 1663–1669. (b) Julia, M. Pure Appl.

Chem. 1967, 15, 167–183. (c) Testaferri, L.; Tiecco, M.; Spagnolo, P.;

Zanirato, P.; Martelli, G. J. Chem. Soc., Perkin Trans. 2 1976, 662–668.

(d) Santi, R.; Bergamini, F.; Citterio, A.; Sebatiano, R.; Nicolini, M.

J. Org. Chem. 1992, 57, 4250–4255. (e) Lei, C.; Mallouk, T. E. Chem.

Commun. 1993, 1359–1361. (f) Bravo, A.; Bjørsvik, H.-R.; Fontana, F.;

Liguori, L.; Mele, A.; Minisci, F. J. Org. Chem. 1997, 62, 7128–7136.

(g) Cerreti, A.; D’Annibale, A.; Trogolo, C.; Umani, F. Tetrahedron Lett.

2000, 41, 3261–3264. (h) Cordero-Vargas, A.; Pꢀerez-Martín, I.; Quiclet-Sire,

B.; Zard, S. Z. Org. Biomol. Chem. 2004, 2, 3018–3025. (i) Alagoz, O.; Yılmaz,

M.; Pekel, A. T. Synth. Commun. 2006, 36, 1005–1013. (j) Amos, R. I. J.;

Smith, J. A.; Yates, B. F.; Schiesser, C. H. Tetrahedron 2010, 66, 7600–7604.

(56) Citterio, A.; Santi, R.; Fiorani, T.; Strologo, S. J. Org. Chem.

1989, 54, 2703–2712.

(57) Eberson, L.; Hartshorn, M. P.; Persson, O.; Robinson, W. T.;

Timmerman-Vaughan, D. J. Acta Chem. Scand. 1995, 49, 482–494.

(58) Br€uckner,R.Reaktionsmechanismen, 2. Auﬂ.; Spektrum Akademischer

Verlag: Heidelberg, 2003.

(38) (a) Paras, N. A.; MacMillan, D. W. C. J. Am. Chem. Soc. 2002,

124, 7894–7895. (b) Saaby, S.; Fang, X.; Gathergood, N.; Jørgensen,

K. A. Angew. Chem., Int. Ed. 2000, 39, 4114–4116.

(39) (a) Bertrand, S.; Hoﬀmann, N.; Pete, J.-P.; Bulach, V. Chem.

Commun. 1999, 2291–2292. (b) Bertrand, S.; Hoﬀmann, N.; Humbel,

S.; Pete, J.-P. J. Org. Chem. 2000, 65, 8690–8703.

(59) Eberson, L. Electron Transfer Reactions in Organic Chemistry;

Springer-Verlag: Berlin, 1987.

(60) (a) Kochi, J. K. Angew. Chem., Int. Ed. Engl. 1988, 27, 1227–1266.

(b) Amatore, C.; Kochi, J. K. Adv. Electron Transfer Chem. 1991, 1, 55–148.

(c) Kochi, J. K. Acc. Chem. Res. 1992, 25, 39–47. See also:(d) Rosokha, S. V.;

Kochi, J. K. Acc. Chem. Res. 2008, 41, 641–653.

(40) Marinkoviꢀc, S.; Hoﬀmann, N. Eur. J. Org. Chem. 2004, 3102–

(61) Bockman, T. M.; Kochi, J. K. J. Phys. Org. Chem. 1994,

3107.

7, 325–351.

(41) In these studies we have observed deuterium transfer from a

reaction intermediate possessing an aromatic amine moiety to a

furanone derivative. The isotopic labeling was used to prove that the

reduction of the furanone derivative leading to two byproduct is linked

to the desired reaction.

(62) For controversial discussion see: (a) Eberson, L.; Hartshorn,

M. P.; Radner, F. Acta Chem. Scand. 1994, 48, 937–950. (b) Eberson, L.;

Hartshorn, M. P.; Radner, F. Adv. Carbocation Chem. 1995, 2, 207–263.

(c) Ridd, J. H. Acta Chem. Scand. 1998, 52, 11–22.

(63) Olah, G. A.; Malhotra, R.; Narang, S. C. Nitration, Methods and

(42) Bowman, R. M.; Chamberlain, T. R.; Huang, C.-W; McCullough,

Mechanisms; VCH: Weinheim, 1989.

J. J. J. Am. Chem. Soc. 1974, 96, 692–700.

(64) Parsons, A. F. An Introduction to Free Radical Chemistry; Black-

well Science: Oxford, 2000.

(43) (a) Ohashi, M.; Tanaka, Y.; Yamada, S. Tetrahedron Lett. 1977,

18, 3629–3632. (b) Mangion, D.; Frizzle, M.; Arnold, D. R.; Cameron,

T. S. Synthesis 2001, 1215–1222.

(44) For an estimation based on redox potentials of the competition

between photochemical electron transfer induced reactions and

photocycloadditions, see: (a) M€uller, F.; Mattay, J. Chem. Rev. 1993,

93, 99–117. (b) Mattay, J. Angew. Chem., Int. Ed. Engl. 1987, 26, 825–845.

(45) Wagner, P. J.; Kemppainen, A. E. J. Am. Chem. Soc. 1968,

90, 5896–5897.

(46) Bertrand, S.; Hoﬀmann, N.; Pete, J.-P. Eur. J. Org. Chem.

2000, 2227–2238.

(47) Bertrand, S. PhD Thesis, Universitꢀe de Reims Champagne-

Ardenne, 1999.

(65) (a) Calvert, J. L.; Eberson, L.; Hartshorn, M. P.; Maclagan, R. G.

A. R.; Robinson Aust. J. Chem. 1994, 47, 1591–1604. (b) Simionescu,

C. I.; Grigoras, M.; Cianga, I.; Olaru, N. Eur. Polym. J. 1998, 34, 891–898.

(c) Sharma, K. K.; Boyd, R. J. Theoret. Chim. Acta 1979, 53, 309–317.

(d) Sankararaman, S.; Kochi, J. K. J. Chem. Soc. Perkin Trans. 2 1991, 1–12.

(66) A radical or charge combination of radical ion pair in Scheme 3

might also be considered. In addition to the outlined arguments against

such a step in the present reaction, one should underline that such a

transformation would lead preferentially to CꢀC bond formation in the

β-position of the furanone. The resulting intermediates carrying a

negative charge or an unpaired electron at the furanone moiety are

stabilized via delocalization of the negative charge or the electron at the

carboxyl function. Such a stabilization is not possible when a CꢀC bond

is formed in the R-position.

(67) A direct reaction of radical II with 1 (Scheme 6) without

previous electron transfer is improbable. In a corresponding direct reaction

of electrophilic triﬂuoromethyl radicals with 1-aminonaphthalene, 1-amino-

2-(triﬂuoromethyl)naphthalene, and 1-amino-4-(triﬂuoromethyl)naph-

thalene were isolated in a 1/1 ratio. In this case, no reaction was detected

in position 4. Strekowski, L.; Hojjat, M.; Patterson, S. E.; Kiselyov, A. S.

J. Heterocycl. Chem. 1994, 31, 1413–1416.

(48) Montalti, M.; Credi, A.; Prodi, L; Gandolﬁ, M. T. In Handbook

of Photochemistry, 3rd ed.; CRC Taylor & Francis: Boca Raton, 2006.

(49) The corresponding electron transfer at the ground state would

be endothermic with DG_ET= +3.02 eV (+70 kcal/mol).

(50) Michl J. In Montalti, M.; Credi, A.; Prodi, L.; Gandolﬁ, M. T.

Handbook of Photochemistry, 3rd ed.; CRC Taylor & Francis: Boca

Raton, 2006; pp 1ꢀ47.

(51) Weller, A. Pure Appl. Chem. 1968, 16, 115–123.

(52) Lewis, F. D. Acc. Chem. Res. 1986, 19, 401–405.

(68) Borck, J.; Dahm, J.; Koppe, V.; Kr€amer, J.; Schorre, G.; Hovy,

J. W. H.; Schorscher, E. (Merck-Anlagen-GmbH) German Patent DE

1695385 (A1), 1971.

(53) (a) Fischer, H.; Radom, L. Angew. Chem., Int. Ed. 2001,

40, 1340–1371. (b) De Vleeschouwer, F.; Jaque, P.; Geerlings, P.;

Toro-Labbꢀe, A.; De Proft, F. J. Org. Chem. 2010, 75, 4964–4974.

7117

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

The Journal of Organic Chemistry

ARTICLE

(69) Often, the construction of such a structural element is particu-

larly challenging: (a) Quaternary Stereocenters; Christoﬀers, J.; Baro, A.,

Eds.; Wiley-VCH: Weinheim, 2005. (b) Bella, M.; Gasperi, T. Synthesis

2009, 1583–1614. (c) Trost, B. M.; Jiang, C. Synthesis 2006, 369–396.

(d) Denissova, I.; Barriault, L. Tetrahedron 2003, 59, 10105–10146.

(e) Christoﬀers, J.; Mann, A. Angew. Chem., Int. Ed. 2001, 40, 4591–4597.

(f) Corey, E. J.; Guzman-Perez, A. Angew. Chem., Int. Ed. 1998,

37, 388–401. (g) Fuji, K. Chem. Rev. 1993, 93, 2037–2066. (h) Martin,

S. Tetrahedron 1980, 36, 419–460.

Ber. 1996, 129, 925–935. (c) Schindler, W.; Kisch, H. J. Photochem.

Photobiol. A: Chem. 1997, 103, 257–264. (d) Hopfner, M.; Weiss, H.;

Meissner, D.; Heinemann, F. W.; Kisch, H. Photochem. Photobiol. Sci.

2002, 1, 696–703.

(84) It must be pointed out that in the case of semiconductor

mediated radical addition of tertiary amines such as N-methylpyrrolidine

to furanones such side products were not observed.¹³In these cases, the

addition of occurs in the β-position of the fuanones.

(85) Fox, M. A. Acc. Chem. Res. 1983, 16, 314–321.

(70) See for example: (a) Matsumura, K.; Mori, T.; Inoue, Y. J. Am.

Chem. Soc. 2009, 131, 17076–17077. (b) Rathore, R.; Lindeman, S. V.;

Kochi, J. K. J. Am. Chem. Soc. 1997, 119, 9393–9404. (c) Kobayashi, T.;

Yoshihara, K.; Nagakura, S. Bull. Chem. Soc. Jpn. 1971, 44, 2603–2610.

(71) Marinkoviꢀc, S.; Brulꢀe, C.; Hoﬀmann, N.; Prost, E.; Nuzillard,

J.-M.; Bulach, V. J. Org. Chem. 2004, 69, 1646–1651.

(86) See for example: (a) Shiragami, T.; Pac, C.; Yanagida, S.

J. Chem. Soc., Chem. Commun. 1989, 831–832. (b) Choi, W.; Hoﬀmann,

M. R. Environ. Sci. Technol. 1995, 29, 1646–1654. (c) Kim, S.; Park, H.;

Choi, W. J. Phys. Chem. B 2004, 108, 6402–6411. (d) Ward, M. D.; Bard,

A. J. J. Phys. Chem. 1982, 86, 6599–3605.

(87) Mꢀedebielle, M.; Keirouz, R.; Okada, E.; Ashida, T. Synlett

(72) See also: (a) Feringa, B. L.; de Lange, B.; Jansen, J. F. G. A.; de

Jong, J. C.; Lubben, M.; Faber, W.; Schudde, E. P. Pure Appl. Chem.

1992, 64, 1865–1871. (b) Moradei, O. M.; Paquette, L. A.; Peschko, C.;

Danheiser, R. L. Org. Synthesis 2003, 80, 66–73. (c) Hashem, A.;

Kleinpeter, E. Adv. Heterocycl. Chem. 2001, 81, 107–165.

2001, 821–823.

(88) Landgraf, S. Spectrochim. Acta A 2001, 57, 2029–2048.

(73) (a) Hoﬀmann, N. Tetrahedron Asymmetry 1994, 5, 879–886.

(b) Brulꢀe, C.; Hoﬀmann, N. Tetrahedron Lett. 2002, 43, 69–72.

(c) Shvydkiv, O.; Yavorskyy, A.; Nolan, K.; Youssef, A.; Riguet, E.;

Hoﬀmann, N.; Oelgem€oller, M. Photochem. Photobiol. Sci. 2010,

9, 1601–1603. (d) Yavorskyy, A.; Shvydkiv, O.; Nolan, K.; Hoﬀmann,

N.; Oelgem€oller Tetrahedron Lett. 2011, 52, 278–280.

(74) (a) Fayadh, J. M.; Swan, G. A. J. Chem. Soc. C 1969, 1781–1969.

(b) Mattay, J.; Banning, A.; Bischof, E. W.; Heidbreder, A.; Runsink, J.

Chem. Ber. 1992, 125, 2119–2127.

(75) Zhang, X.-M.; Mariano, P. S. J. Org. Chem. 1991, 56, 1655–

1660.

(76) For the contribution of polar eﬀects in radical addition to

alkenes and the properties of R-aminoalkyl radicals, see: (a) Giese, B.;

Mehl, W. Tetrahedron Lett. 1991, 32, 4275–4278. (b) Lefort, D.; Fossey,

J.; Sorba, J. New J. Chem. 1992, 16, 219–232. (c) Tedder, J. M. Angew.

Chem., Int. Ed. Engl. 1982, 21, 401–410. (d) Lalevꢀee, J.; Allonas, X.;

Genet, S.; Fouassier, J.-P. J. Am. Chem. Soc. 2003, 125, 9377–9380.

(e) Lalevꢀee, J.; Allonas, X.; Fouassier, J.-P. J. Phys. Chem. A 2004,

108, 4326–4334. (f) Lalevꢀee, J.; Allonas, X.; Fouassier, J.-P. J. Org. Chem.

2005, 70, 814–819.

(77) (a) Bringmann, G.; Mortimer, A. J. P.; Keller, P. A.; Gresser,

M. J.; Garner, J.; Breuning, M. Angew. Chem., Int. Ed. 2005,

44, 5384–5427. (b) Clayden, J.; Moran, W. J.; Edwards, P. J.; LaPlante,

S. R. Angew. Chem., Int. Ed. 2009, 48, 6398–6401.

(78) (a) Kumar, A.; Kumar, M.; Gupta, M. K. Tetrahedron Lett. 2009,

50, 7024–7027. (b) Michael, J. P.; de Koning, C. B.; Hosken, G. D.;

Stanbury, T. V. Tetrahedron 2001, 57, 9635–9648.

(79) (a) Legrini, O.; Oliveros, E.; Braun, A. M. Chem. Rev. 1993,

93, 671–698. (b) Hoﬀmann, M. R.; Martin, S. T.; Choi, W.; Bahnemann,

D. W. Chem. Rev. 1995, 95, 69–96. (c) Linsebligler, A. L.; Lu, G.; Yates,

J. T., Jr. Chem. Rev. 1995, 95, 735–758. (d) Herrmann, J. M. Catal. Today

1999, 53, 115. (e) Lacombe, S.; Tran-Thi, T.-H.; Guillard, C.; Herrmann,

J.-M.; Keller-Spitzer, V.; Keller, N.; Maurette, M.-T.; Pischat, P.; Pigot, T.;

Pulgarin, C.; Rincon, A.-G.; Robert, D. Actual. Chim. 2007, No. 308ꢀ309,

79–93.

(80) (a) Fox, M. A.; Dulay, M. T. Chem. Rev. 1993, 93, 341–357.

(b) Kisch, H. Adv. Photochem. 2001, 26, 93–143. (c) Maldotti, A.;

Molinari, A.; Amadelli, R. Chem. Rev. 2002, 102, 3811–3836. (d) Shiraishi,

Y.; Hirai, T. J. Photochem. Photobiol. C: Photochem. Rev. 2008, 9, 157–170.

(e) Palmisano, G.; García-Lꢀopez, E.; Marcí, G.; Loddo, V.; Yurdakal, S.;

Augugliaro, V.; Palmisano, L. Chem. Commun. 2010, 7074–7089.

(81) (a) Cermenati, L.; Richter, C.; Albini, A. Chem. Commun.

1998, 805–806. (b) Cermenati, L.; Mella, M.; Albini, A. Tetrahedron

1998, 54, 2575–2582.

(82) Serpone, N.; Lawless, D.; Khairudinov, R.; Pelizzetti, E. J. Phys.

Chem. 1995, 99, 16655–16661.

(83) (a) K€unneth, R.; Feldmer, C.; Knoch, F.; Kisch, H. Chem.—

Eur. J. 1995, 1, 441–448. (b) Schindler, W.; Knoch, F.; Kisch, H. Chem.

7118

dx.doi.org/10.1021/jo201080m |J. Org. Chem. 2011, 76, 7104–7118

Article Doi

Photochemical electron transfer mediated addition of naphthylamine derivatives to electron-deficient alkenes

DOI: 10.1021/jo201080m

Source and publish data:

Authors:

Article abstract of DOI:10.1021/jo201080m

Full text of DOI:10.1021/jo201080m

Products guided by the article

R&D Labs maybe for 1322877-06-4

Relevant to this article

Hot Product