Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran by a palladium/norbornene-catalyzed ordered reaction sequence

Article abstract of DOI:10.1016/j.tet.2015.05.110

Abstract Developments are reported in the catalytic synthesis of biaryls containing an ortho-carbaldehyde or 6H-dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o-substituted aryl iodides and o-bromobenzyl alcohols proceeds by unsymmetrical aryl-aryl coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an intramolecular redox process to form carbonyl groups or a C-O coupling to six-membered cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures containing the oxidized CHO group in one ring and the reduced CH₂OH in the other is described along with some mechanistic insights.

Full text of DOI:10.1016/j.tet.2015.05.110

Accepted Manuscript
Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran by a
palladium/norbornene-catalyzed ordered reaction sequence
Nicola Della Ca’, Marco Fontana, Di Xu, Mirko Cremaschi, Riccardo Lucentini, Zhi-
Ming Zhou, Marta Catellani, Elena Motti
PII:
S0040-4020(15)00832-7
10.1016/j.tet.2015.05.110
TET 26829
DOI:
Reference:
To appear in: Tetrahedron
Received Date: 1 April 2015
Revised Date: 27 May 2015
Accepted Date: 28 May 2015
Please cite this article as: Della Ca’ N, Fontana M, Xu D, Cremaschi M, Lucentini R, Zhou Z-M,
Catellani M, Motti E, Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran
by a palladium/norbornene-catalyzed ordered reaction sequence, Tetrahedron (2015), doi: 10.1016/
j.tet.2015.05.110.
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Formation of a carbonyl group ortho to a
biaryl structure or a 6H-dibenzopyran by a
palladium/norbornene-catalyzed ordered
reaction sequence
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Nicola Della Ca’a, Marco Fontanaa, Di Xua,b, Mirko Cremaschia, Riccardo Lucentinia, Zhi-Ming Zhoub, Marta
Catellania,* and Elena Mottia,*
a Dipartimento di Chimica and CIRCC, Università di Parma, Parco Area delle Scienze, 17/A, I-43124 Parma,
Italy
b R&D Centre for Pharmaceuticals, School of Chemical Engineering and the Environment, Beijing Institute of
Technology, Beijing 100081, PR China

1
ACCEPTED MANUSCRIPT
Tetrahedron
journal homepage: www.elsevier.com
Formation of a carbonyl group ortho to a biaryl structure or a 6H-dibenzopyran by a
palladium/norbornene-catalyzed ordered reaction sequence
Nicola Della Ca’a, Marco Fontanaa, Di Xua,b, Mirko Cremaschia, Riccardo Lucentinia, Zhi-Ming Zhoub,
Marta Catellania,* and Elena Mottia,*
a Dipartimento di Chimica and CIRCC, Università di Parma, Parco Area delle Scienze, 17/A, I-43124 Parma, Italy
b R&D Centre for Pharmaceuticals, School of Chemical Engineering and the Environment, Beijing Institute of Technology, Beijing 100081, PR China
ARTICLE INFO
ABSTRACT
Article history:
Received
Received in revised form
Accepted
Developments are reported in the catalytic synthesis of biaryls containing an ortho-carbaldehyde
or 6H-dibenzopyrans in the presence of palladium/norbornene as catalyst. The reaction of o-
substituted aryl iodides and o-bromobenzyl alcohols proceeds by unsymmetrical aryl-aryl
coupling to form a seven-membered oxapalladacycle intermediate, which may undergo an
intramolecular redox process to form carbonyl groups or a C–O coupling to six-membered
cyclic ethers. The predominant formation of dibenzopyrans as well as of biaryl structures
containing the oxidized CHO group in one ring and the reduced CH2OH in the other is described
along with some mechanistic insights.
Available online
Palladium
Norbornene
Catalysis
2009 Elsevier Ltd. All rights reserved
.
C–H activation
Sequential reactions
1. Introduction
aryl bromides containing an electron-withdrawing substituent, or
an ortho chelating group, could be a winning combination for the
selective construction of unsymmetrical biaryl derivatives.3
Organopalladium chemistry is one of the most versatile and
powerful techniques for the synthesis of organic compounds.1 In
particular great attention has been focused on sequential reactions
that are highly selective, have mild reaction conditions, use
commercially accessible starting materials and tolerate a great
variety of functional groups.2 In the course of our studies aimed
at the development of new synthetic procedures based on the use
of palladium/norbornene as a unique catalytic system, we have
shown that it is possible to selectively form substituted biaryl
structures by unsymmetrical coupling of aryl iodides and aryl
bromides followed by an irreversible inter- or intramolecular
step. In order to achieve this goal it is essential to correctly tune
the reactivity of the two aryl halides towards palladium species in
the oxidation state (0) and (II). It has been ascertained that o-
substituted aryl iodides bearing an electron-releasing group and
We have recently reported4 that a biaryl structure containing
an ortho carbaldehyde or a 6H-dibenzopyran derivative could be
conveniently obtained through the one-pot reaction of an ortho-
substituted aryl iodide with a 2-bromobenzyl alcohol derivative.
terminated either by an intramolecular redox process, which
affects both rings of the biaryl structure, or by ring closure across
the two aromatic rings. Under the conditions previously reported
the chemoselectivity of the process was essentially determined by
the alcohol moiety: primary and tertiary alcohols selectively led
to o-biaryl aldehydes and dibenzopyrans, respectively, while
secondary alcohols gave rise to a mixture of ketones and
dibenzopyran derivatives (Scheme 1).
Scheme 1. Palladium/norbornene catalyzed synthesis of o-biaryl carbaldehydes and dibenzopyran derivatives.
Corresponding author. Tel.: +39-0521-905415; fax: +39-0521-905472; e-mail: marta.catellani@unipr.it (M. Catellani)
Corresponding author.Tel.: +39-0521-905414; fax: +39-0521-905472; e-mail: elena.motti@unipr.it (E. Motti)

2
Tetrahedron
ACCEPTED MANUSCRIPT
In continuation of this work we have found that
h molar ratio norbornene to Pd 5:1
dibenzopyran derivatives could also be obtained predominantly
either from primary or secondary benzyl alcohols and that
interesting biaryl derivatives containing an aldehyde group in one
ring and a hydroxymethyl in the other could be readily prepared
through unsymmetrical aryl-aryl coupling of two molecules of o-
iodobenzyl alcohols. In this manuscript developments of the
catalytic reactions are described and some mechanistic aspects
involved in the process are discussed.
Pd(0) precursors such as PdCl2, PdCl2(MeCN)2, Pd(OAc)2 and
Pd2(dba)3 were initially tested in DMF using K2CO3 as a base
(entries 1–4). Among these, Pd(OAc)2 gave the best results in
terms of yield and halide conversion, but not in terms of
selectivity; both compounds 3aa and 4aa were obtained in
comparable yields (entry 4). The effect of the bases was
evaluated using Pd(OAc)2 in DMF. Cs2CO3 gave results similar
to K2CO3, while Na2CO3 or NaHCO3 afforded very low yields
and conversions (entries 4–6). Cesium pivalate (CsOPiv) was
found to be the best base leading to the formation of only the o-
biaryl carbaldehyde 3aa (74% yield); dibenzopyran derivative
4aa was not detected in the reaction mixture by GC analysis
(entry 11). All other bases afforded either comparable or lower
yields (entries 7–10). Different temperatures, reaction times and
solvents were tested using Pd(OAc)2 as catalyst and CsOPiv as a
base. DMA performed similarly to DMF while acetonitrile led to
modest conversion (entries 12 and 13). The best temperature was
105°C; low conversion was obtained at 80°C and poor selectivity
at 120°C (entries 14–15). The amount of norbornene was crucial
and reducing the molar ratio to Pd from 20:1 to 5:1 gave
carbaldehyde 3aa in 95% yield (entry 16).
2. Results and Discussion
2.1. Primary o-bromobenzyl alcohols
2.1.1. Synthesis of o-biaryl carbaldehydes
In our initial studies, the reaction of 1-iodo-2-
isopropylbenzene (1a) with 2-bromobenzyl alcohol (2a) in the
presence of palladium and norbornene as catalysts was chosen as
model to investigate the reaction conditions for the selective
synthesis of the o-biaryl carbaldehyde 3aa. The results are
summarized in Table 1.
Table 1
Screening of reaction conditions for the synthesis of o-biaryl
carbaldehyde 3aa from 1-iodo-2-isopropylbenzene 1a and o-
bromobenzyl alcohol 2aa
Table 2
Synthesis of o-biaryl carbaldehydes 3: selected significant
examplesa,4
entry catalyst
base
3aa
4aa
yield (%)b yield (%)b
_______________________________________
1
2
3
4
5
6
7
8
PdCl2
K2CO3
29
39
11
32
12
6
-
24
21
-
18
-
-
-
-
-
5
-
PdCl2(MeCN)2 K2CO3
Pd2(dba)3
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
Pd(OAc)2
K2CO3
K2CO3
Cs2CO3 35
Na2CO3 15
K3PO4
25
-
35
67
c
NEt3
9
KOAc
KOPiv
10
11
12d
13e
14f
15g
CsOPiv 74
CsOPiv 72
CsOPiv 41
CsOPiv 32
CsOPiv 57
CsOPiv 95
5
-
16h
a
Reaction conditions: molar ratio of 1a, 2a, Pd catalyst,
norbornene and base 20:20:1:20:50; 2.2 × 10-3 mmol Pd/mL
DMF; under N2, 105 °C, 24 h.
b GC and/or 1H NMR yield on the charged amount of 1a.
c molar ratio of the base to palladium 100:1.
d DMA
_________________________________________
a
Reaction conditions: aryl iodide 1 (0.36 mmol), o-
e MeCN, refluxing
f 80 °C
g 120 °C
bromobenzyl alcohol 2 (0.36 mmol), norbornene (0.18 mmol),
Pd(OAc)2 (0.018 mmol), CsOPiv (0.90 mmol) in DMF (8 mL),
under N2 at 105° C for 24 h; isolated yields based on the charged
amount of the aryl iodide.

3
b Molar ratio of norbornene to Pd = 5:1.
c Molar ratio of norbornene to Pd = 20:1.
OMe
OH
OMe
OH
ACCEPTED MANUSCRIPT
CHO
O
O
Under our best conditions the scope of the reaction was
evaluated by using different o-substituted aryl iodides and o-
bromobenzyl alcohols. It was noticed, however, that a reduced
amount of norbornene (5:1 molar ratio to Pd), although
appropriate for 1-iodo-2-isopropylbenzene, led to poor results
with some other substrates. Thus norbornene was used in a molar
ratio to palladium ranging from 5:1 to 20:1. Table 2 reports
significant examples obtained with different substituents in the
starting aryl iodides and o-bromobenzyl alcohols.4 The reaction
afforded biarylaldehydes 3 in good to excellent yields. Better
yields were observed especially in the presence of bulky ortho
groups on the starting aryl iodides and when electron-donating
substituents were present in both of the aryl rings.
4
H, CO2Me
CHO
71%
MeO
O
MeO
O
13%
a
Reaction conditions: o-iodobenzyl alcohol 5 (0.72 mmol),
norbornene (0.36 mmol), Pd(OAc)2 (0.018 mmol), K2CO3 (0.90
mmol) in DMF (8 mL), under N2 at 105° C for 24 h.
b
Isolated yield based on the charged amount of the o-
iodobenzyl alcohol 5.
c Two diastereoisomers in 1:1 molar ratio.
Interesting biaryl derivatives containing a CH2OH group on
one aromatic ring and a CHO on the other were obtained when
two molecules of o-iodobenzyl alcohol were allowed to react
under the conditions reported in Table 3. In addition to the
straightforward synthesis of these 3’-hydroxymethyl-[1,1’]-
biphenyl-2-carbaldehydes,5 which occurs with satisfactory yields
both in the presence of electron-donating and electron-
withdrawing groups (entries 2–3 and 4), the selective oxidation
of only the ortho CH2OH group has some bearing on the reaction
mechanism (see infra). In this case, however, formation of o-
biaryl carbaldehyde 6 was accompanied by anomalous compound
7, which still retains a norbornyl group as shown in Table 3.
Decreasing the amount of norbornene did not bias the outcome of
the reaction toward compounds 6.
The Scheme reported shows the proposed reaction pathway
for the formation of o-biarylcarbaldehydes
3 and 6H-
dibenzopyran derivatives 4 from aryl iodides 1 and primary o-
bromobenzyl alcohols
catalysis conditions.
2
under our palladium/norbornene
iPr
iPr
iPr
O
I
CHO
Pd0L2
1a
4aa
3aa
iPr
L
iPr
Pd
L
I
L
Table 3
Pd
O
L
I
Reaction of o-iodobenzyl alcohols in the presence of
Pd(OAc)2 and norbornenea
VI
iPr
KBr
Pd
L
I
II
iPr
K2CO3
Br
Pd
Entry R1, R2
6 yield (%)b
7 yield (%)b,c
L
KI
HO
iPr
V
iPr
1
H, H
Pd
L
L
L
Pd
Br
L
Br
III
OH
OH
2a
IV
Scheme 2. Proposed reaction pathway to o-
biarylcarbaldehyde 3aa and dibenzopyran 4aa (L = solvent or
2
H, OMe
coordinating substrates).
The proposed mechanism for the reaction of 1-iodo-2-
isopropylbenzene 1a and o-bromobenzyl alcohol 2a, is relevant
to interpret the role of norbornene along with other reaction
components and to facilitate in the discussion of mechanistic
insights that have been elucidated in the present work.
3
OMe, OMe
The reaction starts with the oxidative addition of Pd(0) to aryl
iodide 1a to form arylpalladium complex I.6 Norbornene
stereoselectively inserts into the C–C bond of I generating

4
Tetrahedron
ACCEPTED MANUSCRIPT
cis,exo arylnorbornylpalladium iodide II,7 which in turn gives
likely to be due to the coordinating ability of the hydroxymethyl
rise to palladacycle III8,3i through aryl C–H bond activation.9
Oxidative addition of o-bromobenzyl alcohol 2a to metallacycle
III affords the Pd(IV) intermediate IV,10 which undergoes
reductive elimination to complex V11 by selective aryl-aryl
coupling. Norbornene deinsertion from V gives an aryl-Pd(II)
intermediate that contains the benzylic OH group in appropriate
position to form the oxapalladacycle VI.12 Depending on the
reaction conditions, complex VI can deliver either the
carbaldehyde 3aa or cyclic derivative 4aa while regenerating
Pd(0) catalyst. While the cyclic compound is formed by C–O
coupling,13 the o-biaryl carbaldehyde is obtained by an
intramolecular redox process, with migration of a hydrogen atom
from the benzylic group to the aryl carbon of the adjacent ring.
group of complex VII (Scheme 3) to form a ring with the
norbornylpalladium species (complex VIII), thus making
deinsertion more difficult. The subsequent formation of aryl
carbaldehyde 7 must therefore be attributed to the migration of a
hydrogen atom from the hydroxymethyl group to the norbornyl
carbon now bonded to palladium, via the oxapalladacycle VIII,
as represented in Scheme 3.
A critical feature of the reaction pathway is the catalytic
character of norbornene participation. 3a-c As shown in Scheme 2,
norbornene is inserted at the beginning of the cycle and expelled
towards the end. The quantity of norbornene in the reaction
mixture is quite crucial since at high concentration it favors the
insertion step (from I to II) while making the deinsertion difficult
(from V to VI). Each substrate may have different requirements
and the proper concentration is found experimentally.
As mentioned in the introduction, it is also appropriate to
stress the need for an accurate balance of the species that give
rise to palladium complex VI. In order to achieve a high yield of
the desired products complex VI must result from comparable
reaction rates of the Pd(II) intermediate I with norbornene to give
the initial palladacycle III on the one hand, and of the
hydroxymethyl bromoarene to afford the palladium(IV) complex
IV on the other. If complex VI is not formed in a timely fashion,
one of the two coupling partners, in particular the iodoarene, that
is usually the most reactive, will undergo cyclization with
norbornene and/or with itself through palladacycle III according
to previously described pathways.3a-c,14 This trend could be
counteracted either by decreasing the norbornene concentration
by up to one fourth (as shown in some experiments of Table 2)
and/or by introducing electron-releasing substituents on the
iodoarene to curtail its reactivity towards the oxidative addition
of palladium(0).
Scheme 3. Oxapalladacycle VIII precludes norbornene
deinsertion and allows benzylic hydrogen transfer to the
palladium-bonded norbornyl group.
Although an intramolecular reaction could hypothetically take
place with the hydroxymethyl group of the other ring, no
aldehyde groups at the 2-position of the biaryl systems were
observed, presumably because the smaller 7-membered
oxapalladacycle VIII is preferred to the larger 9-membered one
IX. This observation lends further support to the proposed
intramolecular mechanism.
Retention of the norbornyl group is also observed in the
absence of the hydroxymethyl group. Other coordinating groups
such as the methoxy have a similar effect (Scheme 4). By
allowing 2-iodoanisole and 2-bromobenzylalcohol to react in the
presence of Pd(OAc)2 and norbornene as catalysts with K2CO3 as
a base in DMF at 105 °C, compound 9, containing the norbornyl
moiety, was isolated as the major product in 52% yield together
with 15% of carbaldehyde 3ja. Lowering the ratio of norbornene
to Pd(OAc)2 from 20:1 to 10:1 did not increase the selectivity
with regard to the formation of 3ja, which was recovered in only
11% yield together with 34% of compound 9. As shown in
Scheme 5, compound 9 originates from the less favored 9-
membered oxapalladacycle ring XII, that appears to be the only
intermediate allowing an easy termination pathway to the
sequential process.
Another important aspect of the reaction is connected with the
dual reactivity of the oxapalladacycle VI: hydrogen transfer from
the benzylic group to the palladium-bonded aryl carbon of the
neighboring ring or reductive elimination by C-O bond
formation, to form carbaldehyde 3aa or dibenzopyran derivative
4aa, respectively.
As previously mentioned, the first evidence for an
intramolecolar redox reaction was evidenced by the fact that the
unsymmetrical aryl coupling reaction of two molecules of an o-
iodobenzyl alcohol led to the formation of the o-
biarylcarbaldehyde 6 (Table 3), as the major product, in accord
with the proposed mechanism of Scheme 2. In this case,
however, both of the aryl rings involved in the redox process
(Scheme 2, type VI intermediate) bear a hydroxymethyl group
and only one is oxidized, giving rise to compound 6 (Table 3)
containing both an aldehyde and an unreacted hydroxymethyl
group. Had
an intermolecular reaction occurred, the
hydroxymethyl groups of the two rings would have been
transformed by oxidation with unbiased selectivity.
Moreover, in this case we observe the formation of compound
7 (Table 3), which still retains a norbornyl group in spite of the
fact that norbornene deinsertion is usually observed in the
mechanism of Scheme 2 (from V to VI) in the presence of bulky
groups adjacent to the aryl-norbornyl bond. This behavior is
Scheme 4. Anomalous behavior caused by the methoxy
group.

5
Table 4
ACCEPTED MANUSCRIPT
Screening of reaction conditions for the synthesis of
dibenzopyran 4aa from 1-iodo-2-isopropylbenzene 1a and o-
bromobenzyl alcohol 2aa
entry base
ligand 3aa
4aa
yield (%)b yield (%)b
1
2
3
4
5
6
7
8
K2CO3 TPP
Cs2CO3 TPP
K3PO4 TPP
27
31
25
29
60
64
12
38
35
29
29
22
17
-
-
64
-
5
56
-
54
-
5
Scheme 5. Oxapalladacycles XI and XII inhibit norbornene
expulsion.
KOAc
TPP
Also noteworthy is that o-bromobenzaldehydes expected from
intermolecular hydrogen transfer, as well as their possible
reaction products with substrates present in solution, have never
been detected. It is well known, however, that intermolecular
hydrogen transfer reactions can readily terminate a palladium
catalyzed reaction sequence.15
KOPiv TPP
CsOPiv TPP
K2CO3 TFP
KOPiv TFP
CsOPiv TFP
K2CO3 mTCPP 10
CsOPiv mTCPP 38
K2CO3 pTCPP 12
KOPiv pTCPP 38
CsOPiv pTCPP 35
9
2.1.2. Deuterium labelling experiment
10
11
12
13
14
To probe the intramolecular hydrogen transfer from the
benzylic group of oxapalladacycle of type VI (Scheme 2) to the
ortho aromatic carbon of the adjacent ring unequivocally, a
control reaction was carried out using (2-bromophenyl)methan-
a
d2-ol as
a
coupling partner with 1-iodo-4-methoxy-2-
Reaction conditions: molar ratio of 1a, 2a, Pd(OAc)2,
methylbenzene 1d (Scheme 6). As revealed by 1H NMR
experiments, the resulting ortho biaryl carbaldehyde 10 (85%
yield) contained one deuterium atom on the aldehydic group and
another in the ortho position of the adjacent aryl ring with almost
complete incorporation of deuterium within the limits of
experimental error.16
norbornene, ligand and base 20:20:1:20:2:50; 2.2 × 10-3 mmol
Pd/mL DMF; under N2, 105 °C, 24 h.
1
b GC and/or H NMR yield on the charged amount of the aryl
iodide 1a.
The effect of ligands, bases and other parameters were
investigated using Pd(OAc)2/norbornene as the catalytic system
in DMF at 105 °C for 24 h (Table 4). The addition of a phosphine
ligand such as TPP (triphenylphosphine) in the presence of
different bases such as K2CO3, Cs2CO3, K3PO4 and KOAc led to
the formation of the o-biaryl carbaldehyde 3aa and cyclic
compound 4aa in comparable amounts (entries 1-4). Switching to
TFP (trifurylphosphine) as the ligand in combination with K2CO3
as a base proved beneficial with regard to the formation of
dibenzopyran derivative 4aa which was obtained in 64% yield
along with 12% of compound 3aa (entry 7). A similar trend was
observed with mTCPP and pTCPP (meta- and para-chloro
triphenylphosphines) with slightly lower yields (entries 10 and
12). The use of KOPiv or CsOPiv as a base offset the positive
effect of TFP, mTCPP and pTCPP with regards to dibenzopyran
formation (entries 8-9, 11 and 13-14). The best molar ratio of
norbornene to Pd(OAc)2 was found to be 20:1.
Scheme 6. Reaction of 1-iodo-4-methoxy-2-methylbenzene
and (2-bromophenyl)methan-d2-ol.
2.1.3. o-Bromobenzyl alcohol 2a: synthesis of
dibenzopyran derivatives
With our optimized conditions in hand we next studied the
scope of the reaction using ortho-substituted aryl iodides as
cross-coupling partners of o-bromobenzyl alcohol 2a (Table 5).
In agreement with previously reported data,14 also 1-iodo-2-
(trifluoromethyl) benzene containing an electron-withdrawing
CF3 group led to the corresponding dibenzopyran derivative in
satisfactory yield.
We then attempted to bias the selectivity of the reaction
towards the formation of dibenzopyran derivatives and
investigated the reaction conditions while consistently using 1-
iodo-2-isopropylbenzene (1a) and 2-bromobenzyl alcohol (2a) as
model substrates. The results are summarized in Table 4.

6
Tetrahedron
ACCEPTED MANUSCRIPT
Table 5
Table 6
Synthesis of dibenzopyrans 4 from ortho-substituted aryl
iodides 1 and o-bromobenzyl alcohol 2aa
Screening of reaction conditions for the synthesis of
dibenzopyran 13aa from 1-iodo-2-isopropylbenzene 1a and 1-
(2-bromophenyl)ethanol 11aa
iPr
iPr
Br
OH
iPr
+
I
Pd(OAc)2/ligand
O
O
+
base, DMF
105 °C, 24h
1a
11a
Entry
1
R1
3 yield (%)b 4 yield (%)b
12aa
13aa
Entry base
ligand 12aa
13aa
yield (%)b yield (%)b
1
K2CO3
-
-
41
31
35
33
35
43
37
7
44
24
31
29
20
48
31
82
39
62
67
34
77
51
69
77
i-Pr
2
Cs2CO3
3
CsOPiv -
4
5
KOPiv
KOAc
-
-
6
7
8
9
K2CO3 TPP
CsOPiv TPP
K2CO3 TFP
CsOPiv TFP
2
3
Me
(CH=CH)2
CF3
35
10
11
12d
13d
14e
15f
K2CO3 mTCPP 14
K2CO3 pTCPP 13
K2CO3
K2CO3 TFP
K2CO3 TFP
K2CO3 TFP
K2CO3 TFP
-
37
15
9
6
9
16g
a
Reaction conditions: molar ratio of 1a, 11a, Pd(OAc)2,
4
norbornene, ligand and base 20:20:1:10:2:50; 2.2 × 10-3 mmol
Pd/mL; DMF as solvent, under N2, 105 °C, 24 h.
1
b GC and/or H NMR yield on the charged amount of the aryl
iodide 1a.
a
Reaction conditions: aryl iodide 1 (0.36 mmol), o-
bromobenzyl alcohol 2a (0.36 mmol), norbornene (0.36 mmol),
Pd(OAc)2 (0.018 mmol), TFP (0.036 mmol) and K2CO3 (0.90
mmol) in DMF (8 mL), under N2 at 105° C for 24 h.
c molar ratio of the base to palladium 40:1.
d DMA
e MeCN
f 80 °C
b Isolated yield on the charged amount of the aryl iodide 1.
2.2. Secondary benzyl alcohols
2.2.1. Synthesis of dibenzopyran derivatives
g 120 °C
As previously observed the reaction of ortho-substituted aryl
iodides with secondary o-bromobenzyl alcohols carried out in the
absence of any stabilizing ligands led to the formation of a
mixture of ketones and dibenzopyran derivatives.4 We have
found that TFP as well as mTCPP and pTCPP had a positive
effect on the C–O reductive elimination pathway of
oxapalladacycle of type VI (Scheme 2) leading predominantly to
the formation of dibenzopyran derivatives. Optimization of the
reaction conditions was carried out using 1-iodo-2-
isopropylbenzene 1a and 1-(2-bromophenyl)ethanol 11a as
model substrates (Table 6). Satisfactory to good results were
obtained except when highly electron rich aryl iodides such as 1-
iodo-4-methoxy-2-methyl and 1-iodo-3,4-dimethoxy-2-methyl-
benzene were used (Table 7, entries 4 and 5).
Table 7
Synthesis of dibenzopyrans 13 from ortho-substituted aryl
iodides 1 and secondary o-bromobenzyl alcohol 11a
12
13
R1, R2. R3
R4
Entry
yield (%)b
yield (%)b

7
of
1-iodo-2-isopropylbenzene
(1a)
and
2-(2-
ACCEPTED MANUSCRIPT
bromophenyl)propan-2-ol (14aa), in the presence of Pd(OAc)2
and norbornene as catalysts, K2CO3 as a base, at 105 °C for 24 h,
afforded cyclic compound 15aaa in 83% yield (Table 8, entry 1).
In our initial studies, this reaction was chosen as a model to
optimize the reaction conditions. The results are summarized in
Table 8.
1
2
3
4
Me, H, H
Me
Me
Me
Me
Table 8
Screening of reaction conditions for the synthesis of
dibenzopyran 15aaa from 1-iodo-2-isopropylbenzene 1a and
2-(2-bromophenyl)propan-2-ol 14aaa
Me, Me, H
iPr
Br OH
iPr
Pd(OAc)2/ligand
O
+
base, DMF
105 °C, 24h
I
iPr, H, H
14aa
1a
15aaa
Entry base
ligand 15aaa
yield (%)b
1
2
3
4
K2CO3
-
83
77
78
80
83
Me, H, OMe
CsOPiv -
KOPiv
-
K2CO3 TPP
K2CO3 TFP
5
6
K2CO3 pTCPP 80
7c
8d
9e
10f
K2CO3
K2CO3
K2CO3
K2CO3
K2CO3
-
-
-
-
-
67
65
82
74
75
5
6
Me, OMe, OMe Me
11g
a
Reaction conditions: molar ratio of 1a, 14aa, Pd(OAc)2,
norbornene, ligand and base 20:20:1:20:2:50; 2.2 × 10-3 mmol
Pd/mL DMF; under N2, 105 °C, 24 h.
(CH=CH)2, H
Me
b
1
GC and/or H NMR yield based on the charged amount of
1a.
c DMA
d MeCN
7
8
(CH=CH)2, OMe
Me
Ph
e 80 °C
f 120 °C
g molar ratio of norbornene to palladium 10:1
K2CO3 was found to be the base of choice in terms of
Me, H, H
dibenzopyran yield and selectivity (entries 1-3); phosphine
ligands, which proved to be crucial for the synthesis of
dibenzopyran rings resulting from primary or secondary benzyl
alcohols, as well as solvent, temperature, amount of norbornene
and base did not significantly affect the yield of dibenzopyran 15
(entries 4-11). As expected due to the absence of benzylic
hydrogens, only the geminal groups have a dramatic effect on
ring closure.17 Dibenzopyran heterocycles 15 containing the
electron-withdrawing trifluoromethyl group were also prepared
(entries 7–8, Table 9) with good yields starting from the
corresponding bromide. Less desirable results were observed
with the corresponding aryl iodide likely because of its increased
reactivity as compared to aryl bromides. The yields were further
increased by using CsOPiv as a base (entries 7-8). The trend
a
Reaction conditions: aryl iodide 1 (0.36 mmol), o-
bromobenzyl alcohol 11 (0.36 mmol), norbornene (0.36 mmol),
Pd(OAc)2 (0.018 mmol), TFP (0.036 mmol) and K2CO3 (0.90
mmol) in DMF (8 mL), under N2 at 105° C for 24 h.
b Isolated yield on the charged amount of the aryl iodide 1.
2.3. Tertiary benzyl alcohols: Synthesis of dibenzopyrans 15
Not surprisingly, given the lack of benzylic hydrogens, the
synthesis of dibenzopyran derivatives starting from tertiary o-
bromobenzyl alcohols and ortho-substituted aryl iodides was
very efficient in terms of both yield and selectivity. The reaction

8
Tetrahedron
ACCEPTED MANUSCRIPT
observed for the substituent effect is similar to that reported in
Table 1.
Table 9
8
CF3
H
Et
Et
Synthesis of dibenzopyrans 15 from ortho-substituted aryl
iodides 1 and tertiary o-bromobenzyl alcohol 14a
a
Reaction conditions: aryl iodide 1 (0.36 mmol), o-
bromobenzyl alcohol 14 (0.36 mmol), norbornene (0.36 mmol),
Pd(OAc)2 (0.018 mmol), K2CO3 (0.90 mmol) in DMF (8 mL),
under N2 at 105° C for 24 h;
b Isolated yields based on the charged amount of 1.
c
1-bromo-2-(trifluoromethyl)benzene in place of 1-iodo-2-
(trifluoromethyl)benzene
15
yield (%)b
Entry R1 R2
R3 R4
d
CsOPiv as base; 1-bromo-2-(trifluoromethyl)benzene in
place of 1-iodo-2-(trifluoromethyl)benzene
In all cases no reaction was observed in the absence of
norbornene. All the steps involved in the formations of o-biaryl
carbaldehydes and dibenzopyran derivatives worked nicely and
led to the desired final products in satisfactory to good yields. In
spite of its complexity the overall reaction can be carried out
under simple and mild conditions, starting from simple building
blocks thus offering a valuable synthetic tool. In particular the
dibenzopyrans presented here are not easily accessible by other
routes including those recently reported.18
1
2
Me 3-Me Me Me
Me 3-Me Et
Et
Et
3. Conclusions
In conclusion, we have developed a methodology for the
synthesis of selectively substituted o-biaryl carbaldehydes and
probed that the reaction mechanism proceeds through an
intramolecular redox process by robust deuterium labelling
experiments and substantial chemical evidence. The predominant
formation of dibenzopyran derivatives starting either from
primary or secondary o-bromobenzyl alcohols as partner of
ortho-substituted aryl iodides has been obtained taking advantage
of the positive effect exerted by TFP. Ligands were not required
when tertiary o-bromobenzyl alcohols were used since ring
closure is strongly favored by the geminal group effect.
3
4
5
Me 4-Me Et
Me H
Me Ph
Me Ph
4. Experimental section
4.1. General
iPr
H
Most starting materials were commercially available and were
used
without
further
purification.
1-Iodo-2-
isopropyliodobenzene, 1-iodo-4-methoxy-2-methylbenzene were
prepared by iodination of the corresponding diazonium salt
according to the literature.19 1-Iodo-3,4-dimethoxy-2-
methylbenzene,20
1-iodo-4-methoxynaphthalene,21
(2-
6
7
(CH=CH)4
Me Ph
bromophenyl)phenylmethanol,22
3-(2-bromophenyl)pentan-3-
ol,17a 2-bromobenzenemethan-d2-ol,23 1-(2-bromophenyl)-1-
phenylethanol,24 (2-iodo-5-methoxyphenyl)methanol,25 (6-iodo-
2,3-dimethoxyphenyl)methanol,25 were prepared according to
procedures adapted from the literature. (5-Carbomethoxy-2-
iodophenyl)methanol was prepared starting from methyl 4-
amino-3-methylbenzoate by diazotization, followed by
bromination of the benzylic group and final hydrolysis.26
CF3
H
Me Me
All palladium-catalyzed reactions were carried out under
nitrogen using standard Schlenk techniques. DMF was dried and
stored over
4 Å molecular sieves under nitrogen. Gas
chromatographic analyses were performed with an Agilent
Technologies 7820A GC System using a 30 m SE-30 capillary

9
4.2.2.3. 3’-Methyl-[1,1’]-biphenyl-2-carbaldehyde
column. Flash column chromatography was carried out on Merck
Kieselgel 60 and TLC on Merck 60F254 plates.
ACCEPTED MANUSCRIPT
(3ba, Table 5, entry 2)4
Mass spectra (EI) were obtained with a Hewlett Packard
instrument working at 70 eV ionization energy. NMR spectra
From 2-iodotoluene (79 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 3ba was
obtained in 10% yield (7 mg). Eluent: hexane.
were recorded in CDCl3 on
a Bruker AVANCE 400
spectrometer, unless otherwise indicated. Chemical shifts are
reported in parts per million using the solvent as internal
reference (7.26 and 77.00 ppm, respectively for 1H and 13C
NMR). The reported assignments are based on decoupling,
COSY, NOESY, HMQC and HMBC correlation experiments.
Interchangeable assignments are marked by an asterisk. IR
4.2.2.4. 4-Methyl-6H-dibenzo[b,d]pyran (4ba, Table
5, entry 2)2 7
From 2-iodotoluene (79 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 4ba was
obtained in 61% yield (43 mg). Eluent: hexane.
spectra were recorded on
a
Nicolet FT-IR 5700
spectrophotometer (Thermo Electron Corporation). Melting
points were determined with an Electrothermal apparatus and are
uncorrected. Elemental analyses were performed with a Carlo
Erba EA 1108-Elemental Analyzer.
4.2.2.5. 2-(Naphthalen-2’-yl)benzaldehyde (3ha,
Table 5, entry 3)4
From 2-iodonaphthalene (91 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 3ha was
obtained in 8% yield (7 mg). Eluent: hexane.
4.2. General procedure
4.2.1. General procedure for the reaction of o-
iodobenzyl alcohols in the presence of norbornene,
Pd(OAc)2 and K2 CO3 in DMF
4.2.2.6. 6H-Benzo[d]naphtho[1,2-b]pyran (4ha,
Table 5, entry 3)4
A DMF solution (8 mL) of the o-iodobenzyl alcohol (0.72
mmol) and norbornene (34 mg, 0.36 mmol) was added under
nitrogen to a Schlenck-type flask containing Pd(OAc)2 (4 mg,
0.018 mmol) and K2CO3 (124 mg, 0.90 mmol). The reaction
mixture was stirred at 105 °C for 24h. After cooling to room
temperature the organic layer was diluted with EtOAc (20 mL),
washed twice with water (20 mL) and dried over Na2SO4. The
solvent was removed under reduced pressure and the resulting
residue was purified by flash chromatography on silica gel using
mixtures of hexane-EtOAc as eluent.
From 2-iodonaphthalene (91 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 4ha was
obtained in 77% yield (64 mg). Eluent: hexane.
4.2.2.7. 3’-(Trifluoromethyl)-[1,1’] -biphenyl-2-
carbaldehyde (3ka, Table 5, entry 4)4
From 1-iodo-2-(trifluoromethyl)benzene - (98 mg, 0.36
mmol), (2-bromophenyl)methanol (67 mg, 0.36 mmol) using
K2CO3 (124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol),
product 3ka was obtained in 6% yield (5 mg). Eluent: hexane.
4.2.2. General procedure for the reaction of o-
substituted aryl iodides with primary, secondary or
tertiary 2-bromobenzyl alcohols in the presence of
norbornene, Pd(OAc)2 , a ligand and a base in DMF
4.2.2.8. 4-(Trifluoromethyl)-6H-dibenzo[b,d]pyran
(4ka, Table 5, entry 4)4
From 1-iodo-2-(trifluoromethyl)benzene (98 mg, 0.36 mmol),
(2-bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.9 mmol) and TFP (8.3 mg, 0.036 mmol), product 4ka was
obtained in 58% yield (52 mg). Eluent: hexane.
A DMF solution (8 mL) of the o-substituted aryl iodide (0.36
mmol), the o-bromobenzyl alcohol (0.36 mmol) and norbornene
(34 mg, 0.36 mmol) was added under nitrogen to a Schlenck-type
flask, containing Pd(OAc)2 (4 mg, 0.018 mmol), the phosphine
(0.036 mmol), when required, and K2CO3 (124 mg, 0.90 mmol)
or CsOPiv (211 mg, 0.90). The reaction mixture was stirred at
105 °C for 24h. After cooling to room temperature the organic
layer was diluted with EtOAc (20 mL), washed twice with water
(20 mL) and dried over Na2SO4. The solvent was removed under
reduced pressure and the resulting residue was purified by flash
chromatography on silica gel using mixtures of hexane-EtOAc as
eluent.
4.2.2.9. 1-(3'-Methyl-[1,1'-biphenyl] -2-yl)ethanone
(12ba, Table 7, entry 1)4
From 2-iodotoluene (79 mg, 0.36 mmol), 1-(2-
bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 (124 mg,
0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 12ba was
obtained in 8% yield (6 mg). Eluent: hexane.
4.2.2.10. 4,6-Dimethyl-6H-dibenzo[b,d]pyran
(13ba, Table 7, entry 1)4
4.2.2.1. 3’-i-Propyl-[1,1’]-biphenyl-2-carbaldehyde
(3aa, Table 5, entry 1)4
From 2-iodotoluene (79 mg, 0.36 mmol), 1-(2-
bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 (124 mg,
0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 13ba was
obtained in 79% yield (60 mg). Eluent: hexane.
From 1-iodo-2-isopropylbenzene (89 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 3aa was
obtained in 12% yield (10 mg). Eluent: hexane.
4.2.2.11. 1-(3'-Methoxy-5'-methyl-[1,1'-biphenyl] -
2-yl)ethanone (12da, Table 7, entry 4)4
4.2.2.2. 4-i-Propyl-6H-dibenzo[b,d]pyran (4aa,
Table 5, entry 1)4
From 1-iodo-4-methoxy-2-methylbenzene (89 mg, 0.36
mmol), 1-(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using
K2CO3 (124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol),
product 12da was obtained in 16% yield (14 mg). Eluent: hexane.
From 1-iodo-2-isopropylbenzene (89 mg, 0.36 mmol), (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 4aa was
obtained in 64% yield (56 mg). Eluent: hexane.

10
Tetrahedron
4.2.2.12. 2-Methoxy-4,6-dimethyl-6H-
(124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product
ACCEPTED MANUSCRIPT
dibenzo[b,d]pyran (13da, Table 7, entry 4)4
13bb was obtained in 69% yield (70 mg). Eluent: hexane/EtOAc
95:5.
From 1-iodo-4-methoxy-2-methylbenzene (89 mg, 0.36
mmol), 1-(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using
K2CO3 (124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol),
product 13da was obtained in 68% yield (59 mg). Eluent: hexane.
4.2.2.21. 4-i-Propyl-6,6-dimethyl-6H-
dibenzo[b,d]pyran (15aaa, Table 8)4
From 1-iodo-2-isopropylbenzene (89 mg, 0.36 mmol), 2-(2-
bromophenyl)propan-2-ol (77 mg, 0.36 mmol) using K2CO3 (124
mg, 0.9 mmol), product 15aaa was obtained in 83% yield (75
mg). Eluent: hexane.
4.2.2.13. 1-(3',4'-Dimethoxy-5'-methyl-[1,1'-
biphenyl] -2-yl)ethanone (12ea, Table 7, entry 5)4
From 1-iodo-3,4-dimethoxy-2-methylbenzene (99 mg, 0.36
mmol), 1-(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using
K2CO3 (124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol),
product 12ea was obtained in 21% yield (20 mg). Eluent
hexane/EtOAc 97:3
4.3. Characterization data
4.3.1. 3’-Hydroxymethyl-[1,1’]-biphenyl-2-carbaldehyde (6,
R1,R2 = H, Table 3, entry 1)
From (2-iodophenyl)methanol (168 mg, 0.72 mmol) using
norbornene (34 mg, 0.36 mmol), product 6 was obtained in 73%
yield (55 mg). Eluent: hexane/EtOAc 9:1. Mp. (hexane): 66 °C.
4.2.2.14. 2,3-Dimethoxy-4,6-dimethyl-6H-
dibenzo[b,d]pyran (13ea, Table 7, entry 5)4
From 1-iodo-3,4-dimethoxy-2-methylbenzene (99 mg, 0.36
mmol), 1-(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using
K2CO3 (124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol),
product 13ea was obtained in 61% yield (58 mg). Eluent
hexane/EtOAc 97:3
1H NMR: δ 9.94 (1H, s, CHO), 8.01 (1H, dd, J = 7.8, 1.4 Hz,
H3), 7.63 (1H, td, J = 7.5, 1.4 Hz, H5), 7.53–7.40 (4H, m, H4,
H5’, H4’, H6), 7.38 (1H, br s, H2’), 7.31–7.24 (1H, m, H6’), 4.75
(2H, s, CH2OH), 2.88 (1H, br s, OH); 13C NMR: δ 192.5 (CHO),
145.8 (C1), 141.2 (C3’), 137.9 (C1’), 133.6 (C5), 133.5 (C2),
130.7 (C6), 129.3 (C6’), 128.5 (C5’), 128.4 (C2’), 127.8 (C4),
127.6 (C3), 126.6 (C4’), 64.8 (CH2OH); MS (EI, 70 eV): M+ 212
(52), m/z 194 (21), 181 (100), 166 (40), 165 (91), 153 (47), 152
(72), 77 (37), 76 (27). IR (neat, cm-1): ν 1693. Anal. Calcd for
C14H12O2: C, 79.22; H, 5.70 Found: C, 79.14; H, 5.72.
4.2.2.15. 1-[2-(Naphthalen-2-yl)phenyl] ethanone
(12ha, Table 7, entry 6)4
From 1-iodonaphthalene (91 mg, 0.36 mmol), 1-(2-
bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 as a base
(124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product
12ha was obtained in 4% yield (4 mg). Eluent: hexane.
4.3.2.
2’-Hydroxymethyl-2-(2”-exo-norbornyl)-[1,1’]-
biphenyl-3-carbaldehyde (7, R1, R2 = H, Table 3, entry 1)
4.2.2.16. 6-Methyl-6H-benzo[d]naphtho[1,2-
b]pyran (13ha, Table 7, entry 6)4
From (2-iodophenyl)methanol (168 mg, 0.72 mmol) using
norbornene (34 mg, 0.36 mmol), product 7 was obtained in 13%
yield (13 mg). Eluent: hexane/EtOAc 9:1. Colorless oil. A 1:1
mixture of two stereoisomers.
From 1-iodonaphthalene (91 mg, 0.36 mmol), 1-(2-
bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 (124 mg,
0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 13ha was
obtained in 88% yield (88 mg). Eluent: hexane.
1H NMR: δ 10.75, 10.72 (1H, 2s, CHO), 7.86 (1H, 2dd, J =
7.4, 1.9 Hz), 7.56 (1H, d further split), 7.42 (1H, t, J = 7.5Hz),
7.35–7.33 (1H, m), 7.29–7.21 (2H, m), 7.18–7.10, (1H, m), 4.40,
4.39 (2H, 2s, CH2OH), 3.14, 3.04 (1H, 2 pst, J 8.5 Hz), 2.39–
2.34, 2.28–2.21 (1H, 2m), 2.21–2.16 (1H, m), 1.71–0.8 (9H, m);
13C NMR: δ 194.0,193.7, 146.8, 146.6, 141.2, 141.1, 140.8,
140.6, 138.4, 138.1, 136.4, 136.3, 135.8, 135.7, 130.3, 129.9,
129.3, 129.2, 128.0, 127.9, 127.3, 127.2, 127.1, 127.0, 125.6,
125.5, 63.1, 63.0, 45.7, 45.6, 43.5, 42.5, 42.3, 42.1, 38.1, 37.5,
37.1, 36.9, 32.7, 31.9, 28.2, 27.8. MS (EI, 70 eV): (M+ - 18) 288
(3), m/z 219 (34), 211 (100), 179 (53), 178 (52), 165 (60), 67
(36). IR (neat, cm-1): ν 1691. Anal. Calcd for C21H22O2: C, 82.32;
H, 7.24 Found: C, 82.22; H, 7.14.
4.2.2.17. 1-[2-(4-Methoxynaphthalen-2-
yl)phenyl]ethanone (12ia, Table 7, entry 7)4
From 1-iodo-4-methoxyonaphthalene (102 mg, 0.36 mmol), 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 12ia
was obtained in 17% yield (17 mg). Eluent: hexane/EtOAc 97:3.
4.2.2.18. 12-Methoxy-6-methyl-6H-
Benzo[d]naphtho[1,2-b]pyran (13ia, Table 7, entry
7)4
From 1-iodo-4-methoxyonaphthalene (102 mg, 0.36 mmol), 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using K2CO3 (124
mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product 13ia
was obtained in 73% yield (74 mg). Eluent: hexane/EtOAc 97:3.
4.3.3.
3’-Hydroxymethyl-4,5’-dimethoxy-[1,1’]-biphenyl-2-
carbaldehyde (6, R1 = H, R2= OMe, Table 3, entry 2)
From (2-iodo-5-methoxyphenyl)methanol (191 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 6 was
obtained in 61% yield (59 mg). Eluent: hexane/EtOAc 8:2.
Colorless oil.
1H NMR: δ 9.89 (1H, s, CHO), 7.44 (1H, brs), 7.31 (1H, d, J =
8.1 Hz), 7.14 (1H, d, J = 8.1 Hz), 6.95 (1H, s), 6.87 (1H, s), 6.75
(1H, s), 4.68 (2H, s, CH2OH), 3.86 (3H, s), 3.80 (3H,s), 2.61 (1H,
br s, OH); 13C NMR: δ 192.0, 145.6, 141.0, 137.3, 133.4, 133.3,
130.3, 128.0, 127.8, 127.5, 126.6, 113.6, 110.9, 64.8, 55.5, 54.3;
MS (EI, 70 eV): M+ 272 (44), m/z 254 (15), 241 (100), 221 (20),
165 (90), 153 (41), 107 (65),76 (47). IR (neat, cm-1):
ν 1691. Anal. Calcd for C16H16O4: C, 70.57; H, 5.92 Found: C,
70.64; H, 5.82.
4.2.2.19. 3'-Methyl-[1,1'-biphenyl] -2-
yl)(phenyl)methanone (12bb, Table 7, entry 8)4
From 2-iodotoluene (79 mg, 0.36 mmol), (2-
bromophenyl)phenylmethanol (95 mg, 0.36 mmol) using K2CO3
(124 mg, 0.90 mmol) and TFP (8.3 mg, 0.036 mmol), product
12bb was obtained in 9% yield (9 mg). Eluent: hexane/EtOAc
95:5.
4.2.2.20. 4-Methyl-6-phenyl-6H-dibenzo[b,d]pyran
(13bb, Table 7, entry 8)4
From 2-iodotoluene (79 mg, 0.36 mmol), (2-
bromophenyl)phenylmethanol (95 mg, 0.36 mmol) using K2CO3

11
4.3.4.
2’-Hydroxymethyl-4’,5-dimethoxy-2-(2”-exo-
1H NMR: δ 9.97 (1H, s, CHO), 8.04 (1H, d, J = 1.2 Hz),
ACCEPTED MANUSCRIPT
norbornyl)-[1,1’]-biphenyl-3-carbaldehyde (7, R1 = H, R2=
8.01 (1H, d, J = 1.2 Hz), 7.91 (1H, dd, J = 8.1, 1.1 Hz), 7.72 (1H,
s), 7.61 (1H, d, J = 8.1 Hz), 7. 54 (1H, s), 4.76 (2H, s, CH2OH),
3.94 (3H, s), 3.88 (3H, s), 2.60 (1H, br s, OH); 13C NMR: δ
192.5, 166.0, 165.7, 145.2, 141.5, 137.0, 133.2, 133.0, 130.9,
130.1, 128.0, 127.8, 127.4, 127.0, 126.7, 64.8, 52.0, 51.8; MS
(EI, 70 eV): M+ 328 (35), m/z 310 (19), 295 (100), 267 (29), 165
(82), 153 (52), 107 (61),76 (60). IR (neat, cm-1):
ν 1721, 1693. Anal. Calcd for C18H16O6: C, 65.85; H, 4.91
Found: C, 65.80; H, 4.82.
OMe, Table 3, entry 2)
From (2-iodo-5-methoxyphenyl)methanol (191 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 7 was
obtained in 12% yield (15 mg). Eluent: hexane/EtOAc 8:2.
Colorless oil. A 1:1 mixture of two stereoisomers.
1H NMR: δ 10.67, 10.65 (1H, 2s, CHO), 7.35 (1H, br d, J =
2.5 Hz), 7.10 (1H, s), 7.03-7.00 (1H, m), 6.84–6.77 (2H, m), 4.33
(2H, s), 3.84 (3H, s), 3.77 (3H, s), 3.00, 2.91 (1H, 2 pst, J 8.3
Hz), 2.31–2.13 (2H, m), 1.81 (1H, s, OH) 1.55-0.9 (8H, m); 13C
NMR: δ 194.2, 193.9, 147.7, 147.6, 140.2, 140.0, 140.8, 140.7,
137.2, 137.0, 136.0, 135.8, 135.6, 135.5, 130.1, 129.9, 129.3,
129.1, 128.1, 127.9, 127.1, 127.0, 113.6, 113.4, 111.0, 110.9,
63.2, 63.1, 55.5, 55.2, 54.5, 54.3, 45.6, 45.5, 43.5, 42.4, 42.3,
42.1, 38.0, 37.5, 37.0, 36.9, 32.9, 31.9, 28.2, 27.7. MS (EI, 70
eV): (M+ - 18) 348 (9), m/z 297 (13), 289 (100), 267 (65), 179
(13), 178 (38), 165 (54), 67 (19). IR (neat, cm-1): ν 1693. Anal.
Calcd for C23H26O4: C, 75.38; H, 7.15 Found: C, 75.33; H, 7.01.
4.3.8.
2’-Hydroxymethyl-4’,5-dicarbomethoxy-2-(2”-exo-
norbornyl)-1,1’-biphenyl-3-carbaldehyde (7, R1= H, R2=
CO2Me, Table 3, entry 4)
From (5-carbomethoxy-2-iodophenyl)methanol (210 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 7 was
obtained in 13% yield (15 mg). Eluent: hexane/EtOAc 7:3.
Colorless oil. A 1:1 mixture of two stereoisomers.
1H NMR: δ 10.76, 10.74 (1H, 2s, CHO), 8.05 (1H, s), 7.92
(1H, d further split, J = 8.1 Hz), 7.82 (1H, s), 7.78 (1H, s), 7.45
(1H, d, J = 8.1 Hz), 4.42 (2H, s), 3.93 (3H, s), 3.86 (3H, s), 3.08,
3.00 (1H, 2 pst, J 8.3 Hz), 2.30–2.11 (2H, m), 1.80 (1H, s, OH)
1.60–0.80 (8H, m); 13C NMR: δ 194.0,193.8, 166.0, 165.8, 165.7,
165.5, 147.7, 147.6, 140.2, 140.0, 140.8, 140.7, 137.2, 137.0,
136.0, 135.8, 135.6, 135.5, 130.1, 129.9, 129.3, 129.1, 128.1,
127.9, 127.1, 127.0, 125.5, 125.4, 125.1, 125.0, 63.1, 63.1, 52.5,
52.2, 51.5, 51.3, 45.4, 45.2, 43.5, 42.2, 42.0, 41.8, 38.5, 37.9,
37.0, 36.8, 32.8, 31.9, 28.0, 27.8. MS (EI, 70 eV): (M+ - 18) 404
(19), m/z 363 (41), 289 (100), 267 (45), 178 (18), 165 (36), 67
(9). IR (neat, cm-1): ν 1721, 1693. Anal. Calcd for C25H26O6: C,
71.07; H, 6.20 Found: C, 71.00; H, 6.23.
4.3.5. 5’-Hydroxymethyl-3,4,3’,4’-tetramethoxy-1,1’-biphenyl-
2-carbaldehyde (6, R1, R2= OMe, Table 3, entry 3)
From (6-iodo-2,3-dimethoxyphenyl)methanol, (212 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 6 was
obtained in 51% yield (60 mg). Eluent: hexane/EtOAc 8:2.
Colorless oil.
1H NMR: δ 9.81 (1H, s, CHO), 7.44 (1H, brs),7.31 (1H, d, J =
7.8 Hz), 7.07 (1H, d, J =7.8 Hz), 6.87 (1H, s), 4.60 (2H, s,
CH2OH), 3.95 (3H, s), 3.87 (3H,s), 3.78 (3H, s), 3.80 (3H,s), 2.53
(1H, br s, OH); 13C NMR: δ 192.2, 145.5, 141.0, 137.3, 133.3,
133.3, 130.0, 128.2, 127.5, 113.4, 113.1, 111.3, 110.9, 64.6,
55.5, 55.3, 54.7, 54.3. MS (EI, 70 eV): M+ 332 (24), m/z 314
(35), 301 (100), 165 (88), 153 (51). IR (neat, cm-1): ν 1693. Anal.
Calcd for C18H20O6: C, 65.05; H, 6.07 Found: C, 65.00; H, 6.02.
4.3.9. 3-Methoxy-2-(2”-exo-norbornyl)-1,1’-
biphenyl-2’-carbaldehyde (9, Scheme 4)
From 2-iodoanisole (84 mg, 0.36 mmol) and (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 9 was obtained in 52% yield (57
mg). Eluent: hexane/EtOAc 9:1. Colorless oil. A 1:1 mixture of
two diastereoisomers.
4.3.6.2’-Hydroxymethyl-4,5,3’,4’-tetramethoxy-2-(2”-exo-
norbornyl)-1,1’-biphenyl-3-carbaldehyde (7, R1, R2= OMe, Table
3, entry 3)
From (6-iodo-2,3-dimethoxyphenyl)methanol, (212 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 7 was
obtained in 13% yield (19 mg). Eluent: hexane/EtOAc 8:2.
Colorless oil. A 1:1 mixture of two stereoisomers.
1H NMR: δ 9.79, 9.76 (1H, 2s further split), 8.03 (1H, d
further split, J = 7.8, 1.5 Hz), 7.62 (1H, t, J = 7.8 Hz), 7.50 (1H, t,
J = 7.8 Hz), 7.29 (1H, t, J = 8.0 Hz), 7.22–7.16 (1H, m), 6.95
(1H, d, J = 8.2 Hz), 6.76 (1H, td, J = 7.4, 1.2 Hz), 3.86 (3H, s),
2.43, 2.38 (1H, 2 pst, J 8.4 Hz), 2.23 (1H, br s), 2.14 (1H, br s),
1.96-1.85 (1H, m), , 1.49-1.14 (4H, m), 1.18-1.08 (1H, m), 0.94-
0.62 (2H, m); 13C NMR: δ 192.5, 192.3, 158.5, 158.4, 147.0,
146.8, 139.6, 139.5, 133.9, 133.4, 133.2, 133.0, 132.9, 131.0,
130.8, 127.7, 127.6, 126.7, 126.6, 126.0, 125.9, 123.2, 122.8,
111.5, 111.4, 54.8, 44.5, 44.4, 42.9, 42.0, 38.9, 37.9, 37.8, 37.7,
37.0, 36.9, 32.9, 32.4, 22.8, 27.7.MS (EI, 70 eV): M+ 306 (89),
m/z 225 (100), 165 (38), 115 (17). IR (neat, cm-1): ν 1693. Anal.
Calcd for C21H22O2: C, 82.32; H, 7.24 Found: C, 82.34; H, 7.16.
1H NMR: δ 10.62, 10.60 (1H, 2s, CHO), 7.40 (1H, brs), 7.26
(1H, d, J = 7.9 Hz), 7.09 (1H, d, J = 7.9 Hz), 4.28 (2H, s), 3.84
(3H, s), 3.78 (3H, s), 3.72 (3H, s), 3.66 (3H, s), 3.03, 2.95 (1H, 2
pst, J 8.4 Hz), 2.30–2.12 (2H, m), 1.83 (1H, s, OH) 1.55–0.8
(8H, m); 13C NMR: δ 192.2, 190.0, 145.7, 145.5, 141.1, 141.0,
137.3, 137.2, 133.3, 133.2, 133.1,133.0, 131.2, 130.0, 128.2,
120.0, 127.5. 127.3, 113.4, 113.3, 113.1,113.0, 111.3, 111.1,
111.0 110.9, 64.6, 64.5, 55.7, 55.6, 55.5, 55.3, 54.7, 54.6, 54.4,
54.3, 45.6, 45.5, 43.5, 42.4, 42.3, 42.1, 38.0, 37.5, 37.0, 36.9,
32.9, 31.9, 28.2, 27.7. MS (EI, 70 eV): (M+ - 18) 408 (15), m/z
357 (19), 349 (100), 267 (35), 178 (38), 165 (45), 67 (22). IR
(neat, cm-1): ν 1691. Anal. Calcd for C25H30O6: C, 70.40; H, 7.09
Found: C, 70.43; H, 7.06.
4.3.10. 3’-Methoxy-[1,1’]-biphenyl-2-carbaldehyde
(3ja, Scheme 4)
From 2-iodoanisole (84 mg, 0.36 mmol) and (2-
bromophenyl)methanol (67 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 3ja was obtained in 15% yield (11
mg). Eluent: hexane/EtOAc 9:1. Colorless oil.
4.3.7. 5’-Hydroxymethyl-4,3’-dicarbomethoxy-1,1’-biphenyl-
2-carbaldehyde (6, R1= H, R2= CO2Me, Table 3, entry 4)
1H NMR: δ 10.02 (1H, s), 8.05 (1H, d further split, J = 7.8
Hz), 7.66 (1H, td, J = 7.6, 1.2 Hz), 7.55–7.43 (2H, m), 7.40 (1H,
t, J = 7.6 Hz), 7.05-6.96 (3H, m), 3.88 (3H, s); 13C NMR: δ
192.4, 146.0, 138.1, 137.7, 133.7, 133.5, 130.9, 130.7, 128.6,
128.2, 127.3, 116.7, 105.4, 55.2; IR (neat, cm-1): ν 1693; MS (EI,
70 eV): M+ 212 (29), m/z 196 (100), 183 (28), 152 (60).Anal.
From (5-carbomethoxy-2-iodophenyl)methanol (210 mg, 0.72
mmol) using norbornene (34 mg, 0.36 mmol), product 6 was
obtained in 71% yield (83 mg). Eluent: hexane/EtOAc 7:3.
Colorless oil.

12
Tetrahedron
Calcd for C14H12O2: C, 79.22; H, 15.08. Found: C, 79.26; H,
1H NMR: δ 7.74 (1H, d, J = 7.6 Hz), 7.63 (1H, dd, J = 8.0, 1.6
ACCEPTED MANUSCRIPT
15.00.
Hz), 7.38 (1H, td, J = 7.6, 1.6 Hz), 7.32 (1H, td, J = 7.21, 1.6
Hz), 7.25–7.18 (2H, m), 7.05 (1H, t, J = 7.6 ), 5.30 (1H, quart, J =
6.4 Hz), 3.41 (1H, quint, J = 7.2 Hz), 1.66 (3H, d, J = 6.4 Hz),
1.31 (3H, d, J = 6.4 Hz), 1.30 (3H, d, J = 6.4 Hz);13C NMR (100
MHz): δ 150.7, 137.6, 136.0, 130.0, 128.0, 127.5, 126.3, 123.8,
122.5, 122.4, 121.5, 120.7, 73.4, 27.1, 22.7, 22.6, 20.0¸ MS (EI,
70 eV): M+ 238 (7), m/z 223 (100), 178 (19), 165 (26), 152 (11).
Anal. Calcd for C17H18O: C, 85.67; H, 7.61 Found: C, 85.44; H,
7.52.
4.3.11. 5’-Methoxy-3’-methyl-2’-d-[1,1’]-
biphenyl-2-carbaldehyde-formyl-d (10, Scheme
6)
From 1-iodo-4-methoxy-3-methylbenzene (89 mg, 0.36
mmol) and 2-bromobenzenemethan-d2-ol (68 mg, 0.36 mmol)
using norbornene (34 mg, 0.36 mmol), product 10 was obtained
in 85% yield (69 mg). Eluent: hexane/EtOAc 97:3. Mp. (hexane):
66 °C.
4.3.15. 1-(3'-isopropyl-[1,1'-biphenyl] -2-
yl)ethanone (12aa, R1 = iPr, R2 ,R3 =H, R4 = Me,
Table 7, entry 3).
From 1-iodo-2-isopropylbenzene (89 mg, 0.36 mmol) and 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 12aa was obtained in 7% yield (6
mg). Eluent: hexane. Colorless oil.
1H NMR: δ 7.60–7.55 (1H, m), 7.55–7.50 (1H, m), 7.47–7.41
(2H, m), 7.37 (1H, d, J = 8.0 Hz), 7.31–7.26 (1H, m), 7.22–7.20
(2H, m), 2.97 (1H, m, J = 6.8 Hz), 1.99 (3H, s) 1.30 (6H, d, J =
6.8 Hz); 13C NMR: δ 205.2, 149.4, 141.1, 140.9, 140.6, 130.7,
130.1, 128.7, 127.8, 127.3, 127.2, 126.2, 126.1, 34.1, 30.4, 24.0
(2C). MS (EI, 70 eV): M+ 238 (100), m/z 223 (65), 178 (34), 165
(67), 152 (54). IR (neat, cm-1): ν 1688. Anal. Calcd for C17H18O:
C, 85.67; H, 7.61 Found: C, 85.34; H, 7.57.
1H NMR: δ 8.04 (1H, dd further split, J = 7.8, 1.6 Hz, H3),
7.64 (1H, td, J = 7.6, 1.6 Hz, H5), 7.54 (1H, td further split, J =
7.6, 1.2 Hz, H4), 7.48 (1H, dd, J = 7.8, 1.2 Hz, H6), 6.81 (1H, d
further split, J = 2.4 Hz, H4’), 6.75 (1H, further split, J = 2.4 Hz,
H2’), 3.86 (3H, s), 2.42 (3H, s); 13C NMR: δ 192.3 (1:1:1 t, JC,D
=
26.6 Hz, CDO), 159.5 (C3’), 146.0 (C1), 139.5 (C3*), 138.8
(C1’*), 133.7 (C2), 133.5 (C5), 130.5 (C6), 127.7 (C4), 127.3
(C3), 123.6 (1:1:1 t, JC,D = 25.6 Hz, C6’), 114.5 (C4’), 112.8
(C2’), 55.3, 21.5; MS (EI, 70 eV): M+ 228 (93), m/z 200 (100),
169 (47), 154 (42). IR (neat, cm-1): ν 1690. Anal. Calcd for
C15H12D2O2: C, 78.92; H, 7.06 Found: C, 78.99; H, 7.02.
4.3.12. 3,4,6-Trimethyl-6H-dibenzo[b,d]pyran
(13la, R1 , R2 = Me, R3 =H, R4 = Me, Table 7,
entry 2).
4.3.16. 3,4,6,6-Tetramethyl-6H-dibenzo[b,d]pyran
(15laa, Table 9, entry 1).
From 1-iodo-2,3-dimethylbenzene (84 mg, 0.36 mmol) and 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 13la was obtained in 75% yield (60
mg). Eluent: hexane. Mp. (hexane): 62 °C.
1H NMR: δ 7.74 (1H, d, J = 7.6 Hz), 7.55 (1H, d, J = 7.6 Hz),
7.40 (1H, t, J = 7.6 Hz), 7.33 (1H, t, J = 7.2 Hz), 7.22 (1H, d
further split, J = 7.2 Hz ), 6.92 (1H, d, J = 8.0 Hz), 5.32 (1H, q, J
= 6.2 Hz), 2.37 (3H, s), 2.28 (3H, s), 1.68 (3H, d, J = 6.2 Hz); 13C
NMR: δ 151.4, 138.3, 135.6, 130.2, 128.0, 127.2, 125.4, 123.9,
123.0, 122.1, 120.1, 120.0, 73.59, 20.20 (2C), 11.70. MS (EI, 70
eV): M+ 224 (17), m/z 209 (100), 178 (9), 165 (31), 152 (18).
Anal. Calcd for C16H16O: C, 85.68; H, 7.19 Found: C, 85.64; H,
7.12.
From 1-iodo-2,3-dimethylbenzene (84 mg, 0.36 mmol) and 2-
(2-bromophenyl)propan-2-ol (77 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15laa was obtained in
86% yield (73 mg). Eluent: hexane. Colorless oil.
1H NMR: δ 7.73 (1H, d, J = 7.8 Hz), 7.51 (1H, d, J = 7.9 Hz),
7.36 (1H, ”t” further split, J = 7.6 Hz), 7.32–7.25 (2H, m), 6.88
(1H, d, J = 8.0 Hz), 2.34 (3H, s), 2.24 (3H, s), 1.68, 1.67 (6H,
2s); 13C NMR: δ 150.6, 139.2, 138.1, 129.4, 127.5, 127.3, 125.6,
123.0, 122.6, 122.1, 119.9, 119.7, 77.3, 27.5 (2C), 20.1, 11.5; MS
(EI, 70 eV): M+ 238 (11), m/z 223 (100), 178 (14), 165 (19), 152
(12). Anal. Calcd for C17H18O: C, 85.67; H, 7.61 Found: C,
85.69; H, 7.58.
4.3.13. 1-(3’,4’-dimethyl-[1,1'-biphenyl] -2-
yl)ethanone (12la, R1 , R2 = Me, R3 =H, R4 = Me,
Table 7, entry 2).
4.3.17. 6,6-Diethyl-3,4-dimethyl-6H-
dibenzo[b,d]pyran (15lbb, Table 9, entry 2).
From 1-iodo-2,3-dimethylbenzene (84 mg, 0.36 mmol) and 3-
(2-bromophenyl)pentan-3-ol (88 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15lbb was obtained in
86% yield (73 mg). Eluent: hexane. Colorless oil.
From 1-iodo-2,3-dimethylbenzene (84 mg, 0.36 mmol) and 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 12la was obtained in 9% yield (7
mg). Eluent: hexane. Colorless oil.
1H NMR: δ 7.77 (1H, d, J = 7.6 Hz), 7.51 (1H, d, J = 8.0 Hz),
7.35 (1H, td, J = 7.6, 1.2 Hz), 7.29 (1H, td, J = 7.6, 1.2 Hz), 7.16
(1H, d further split, J = 7.2 Hz), 6.85 (1H, d, J = 8.0 Hz), 2.34
(3H, s), 2.26 (3H, s), 2.05–1.92 (4H, m), 0.95 (6H, t, J = 7.6
Hz);13C NMR: δ 150.7, 138.1, 136.2, 130.2, 127.3, 126.8, 125.2,
124.6, 122.2, 122.0, 119.5, 119.2, 82.5, 30.5 (2C), 20.1, 11.5, 8.3
(2C); MS (EI, 70 eV): M+ 266 (7), m/z 237 (100), 222 (9), 178
(14), 165 (10). Anal. Calcd for C19H22O: C, 85.67; H, 8.32.
Found: C, 85.64; H, 8.35.
1H NMR: δ 7.55 (1H, dd, J = 8.0, 1.8 Hz) 7.51 (1H, dt, J =
7.21, 1.6 Hz) 7.44-7.38 (2H, m), 7.21 (1H, d, J = 7.6 Hz), 7.15
(1H, brs), 7.09 (1H, dd, J = 7.6, 1.6 Hz ), 2.34 (3H, s), 2.33 (3H,
s), 2.04 (3H, s);13C NMR: δ 205.3, 140.9, 140.7, 138.3, 137.0,
136.4 , 130.6, 130.2, 130.0, 129.9, 127.8, 127.1, 126.3, 30.4,
19.8, 19.5. MS (EI, 70 eV): M+ 224 (100), m/z 178 (29), 165
(13), 152 (10). IR (neat, cm-1): ν 1687. Anal. Calcd for C16H16O:
C, 85.68; H, 7.19 Found: C, 85.58; H, 7.24.
4.3.14. 4-Isopropyl-6-methyl-6H-dibenzo[b,d]pyran
4.3.18. 6,6-Diethyl-2,4-dimethyl-6H-
dibenzo[b,d]pyran (15cbb, Table 9, entry 3).
From 1-iodo-2,4-dimethylbenzene (84 mg, 0.36 mmol) and 3-
(2-bromophenyl)pentan-3-ol (88 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15cbb was obtained in
98% yield (93 mg). Eluent: hexane. M.p.(hexane): 91 °C.
(13aa, R1 = iPr, R2 ,R3 =H, R4 = Me, Table 7, entry
3).
From 1--iodo-2-isopropylbenzene (89 mg, 0.36 mmol) and 1-
(2-bromophenyl)ethanol (72 mg, 0.36 mmol) using norbornene
(34 mg, 0.36 mmol), product 13aa was obtained in 82% yield (70
mg). Eluent: hexane. Colorless oil.

13
1H NMR (300 MHz): δ 7.77 (1H, d, J = 7.6 Hz), 7.40 (1H, br
s), 7.34 (1H, td, J = 7.6, 1.2 Hz), 7.29 (1H, td, J = 7.6, 1.2 Hz),
7.15 (1H, dd, J = 7.6, 1.6 Hz), 6.95 (1H, br s), 2.36 (3H, s), 2.28
(3H, s), 2.02–1.90 (4H, m), 0.93 (6H, t, J = 7.6 Hz); 13C NMR: δ
148.8, 136.7, 131.4, 130.0, 129.3, 127.2, 127.0, 126.5, 124.7,
122.2, 120.9, 120.6, 82.2, 30.5 (2C), 20.9, 15.7, 8.3 (2C); MS
(EI, 70 eV): M+ 266 (5), m/z 237 (100), 222 (7), 178 (10), 165
(6). Anal. Calcd for C19H22O: C, 85.67; H, 8.32. Found: C, 85.74;
H, 8.28.
1H NMR: δ 7.89 (1H, d, J = 7.6 Hz), 7.80–7.75 (1H, m),
ACCEPTED MANUSCRIPT
7.51 (1H, d further split, J = 8.0 Hz), 7.34, 7.31 (2H partly
overlapped, td, J = 7.5, 1.6 Hz, td, J = 7.6, 1.6 Hz), 7.20–7.13
(1H, m), 7.04 (1H, t, J = 7.8 Hz), 1.57 (6H, s); 13C NMR: δ 150.4,
135.7, 128.0, 128.1, 127.4, 126.2 (quart, JC,F = 5.0 Hz), 126.1,
125.0, 123.9 (quart, JC,F = 270.9 Hz), 122.8, 122.2, 120.1, 119.4
(quart, JC,F = 30.5 Hz), 84.0, 27.5 (2C); MS (EI, 70 eV): M+ 278
(7), m/z 249 (100), 232 (10), 221 (23), 165 (14). Anal. Calcd for
C16H13F3O: C, 69.06; H, 4.71. Found: C, 69.12; H, 4.53.
4.3.19. 4,6-Dimethyl-6-phenyl- -6H-
dibenzo[b,d]pyran (15bac, Table 9, entry 4)
4.3.23. 6,6-Diethyl-4-trifluoromethyl-6H-
dibenzo[b,d]pyran (15kbb, Table 9, entry 8)
From 2-iodotoluene (84 mg, 0.36 mmol) and 1-(2-
bromophenyl)-1-phenylethanol (99 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15bac was obtained in
86% yield (88 mg). Eluent: hexane. Colorless oil.
From 1-iodo-2-(trifluoromethyl)benzene (98 mg, 0.36 mmol)
and 3-(2-bromophenyl)pentan-3-ol (88 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15kbb was obtained in
80% yield (87 mg). Eluent: hexane. Colorless oil.
1H NMR: δ 7.79 (1H, d further split, J = 8.2 Hz), 7.55 (1H, d
further split, J = 7.6 Hz), 7.45 (1H, td, J = 7.7, 1.5 Hz), 7.39 (1H,
td, J = 7.2, 1.2 Hz), 7.36-7.30 (3H, m), 7.28-7.18 (3H, m), 7.10
(1H, d further split, J = 7.2 Hz), 6.90 (1H, t, J = 7.8 Hz), 2.42
(3H, s), 2.11 (3H, s); 13C NMR: δ 151.1, 145.2, 137.2, 130.7,
130.0, 128.1, 127.9 (2C), 127.34, 127.33, 126.8, 126.2 (2C),
125.4, 122.8, 122.4, 121.1, 120.6, 81.0, 28.6, 16.1; MS (EI, 70
eV): 286 (36) (M+), m/z 271 (100), 209 (32), 165 (10). Anal.
Calcd for C21H18O: C, 88.08; H, 6.34. Found: C, 88.01; H, 6.39.
1H NMR: δ 7.88 (1H, d, J = 7.6 Hz), 7.81–7.73 (1H, m), 7.51
(1H, d further split, J = 8.0 Hz), 7.38, 7.36 (2H partly overlapped,
td, J = 7.6, 1.6 Hz, td, J = 7.7, 1.6 Hz), 7.20–7.13 (1H, m), 7.03
(1H, t, J = 7.9 Hz), 2.01 (4H, quart, J = 7.6 Hz), 0.91 (6H, t, J =
7.6 Hz); 13C NMR: δ 151.4, 136.0, 128.2, 128.1, 127.6, 126.5
(quart, JC,F = 5.0 Hz), 126.2, 125.0, 123.7 (quart, JC,F = 270.9 Hz),
122.9, 122.2, 120.0, 119.1 (quart, JC,F = 30.5 Hz), 84.2, 30.9
(2C), 7.9 (2C); MS (EI, 70 eV): M+ 306 (3), m/z 277 (100), 262
(12), 249 (10), 165 (9). Anal. Calcd for C18H17F3O: C, 70.58; H,
5.59. Found: C, 70.60; H, 5.53.
4.3.20. 6-Methyl-6-phenyl-4-isopropyl-6H-
dibenzo[b,d]pyran (15aac, Table 9, entry 5)
Acknowledgements
From 1-iodo-2-isopropylbenzene (89 mg, 0.36 mmol) and 1-
(2-bromophenyl)-1-phenylethanol (99 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15aac was obtained in
93% yield (104 mg). Eluent: hexane. Colorless oil.
Financial support by MIUR and Parma University is gratefully
acknowledged. NMR facilities were provided by Centro
Interdipartimentale Misure “Giuseppe Casnati” of the Università
di Parma. We thank Dr. Jesse Waldo for critical revision and
editing of the manuscript. M.Cr. was recipient of a fellowship
from CIRCC and D.X. from the Beijing Institute of Technology,
Beijing, PR China.
1H NMR: δ 7.80 (1H, dd, J = 7.8 Hz, 1.3 Hz), 7.58 (1H, dd, J
= 7.7, 1. 5 Hz), 7.43 (1H, td, J = 7.8, 1.4 Hz), 7.4-7.32 (3H, m,
with a triplet centered at 7.35 ppm, J = 7.4, 1.3 Hz), 7.32-7.18
(5H, m, with a dd centered at 7.20 ppm, J = 7.7, 1.3 Hz), 6.99
(1H, t, J = 7.7 Hz), 3.63 (1H, hept, J = 6.8 Hz), 2.09 (3H, s), 1.31
(3H, d; J = 6.8 Hz), 1.28 (3H, d, J = 6.8 Hz); 13C NMR: δ 149.8,
145.0, 137.7, 137.5, 130.1, 128.1, 127.9 (2C), 127.4, 127.3, 126.6
(2C), 126.3, 125.4, 122.8, 122.4, 121.4, 120.4, 81.0, 27.9, 26.3,
23.6, 22.6; MS (EI, 70 eV): 314 (36) (M+), m/z 299 (100), 283
(15), 237 (28), 221 (12). Anal. Calcd for C23H22O: C, 87.86; H,
7.05. Found: C, 87.81; H, 7.00.
References and notes
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4.3.21. 6-Methyl-6-phenyl-6H-benzo[d]naphtho[1,2-
b]pyran (15hac, Table 9, entry 6)
From 1-iodonaphthlene (91 mg, 0.36 mmol) and 1-(2-
bromophenyl)-1-phenylethanol (99 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15hac was obtained in
88% yield (101 mg). Eluent: hexane. Colorless oil.
1H NMR: δ 8.59 (1H, d, J = 7.6 Hz), 7.87–7.78 (3H, m), 7.63
(1H, td, J = 8.0, 1.2 Hz), 7.59–7.41 (7H, m), 7.27–7.21 (3H, m),
2.26 (3H, s); 13C NMR: δ 148.3, 145.0, 136.6, 134.3, 129.8,
128.2, 128.2, 127.9, 127.8, 127.6, 127.3, 126.4, 125.9 (2C),
125.7, 125.4, 122.4, 122.2, 121.2, 120.6, 81.7, 28.5; MS (EI, 70
eV): 322 (48) (M+), m/z 307 (100), 245 (42), 215 (17), 202 (11).
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5.53.
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and 2-(2-bromophenyl)propan-2-ol (77 mg, 0.36 mmol) using
norbornene (34 mg, 0.36 mmol), product 15kaa was obtained in
88% yield (87 mg). Eluent: hexane. Colorless oil.
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.

ACCEPTED MANUSCRIPT
Supplementary Data
for
Formation of a carbonyl group ortho to a biaryl structure or a 6H-
dibenzopyran by a palladium/norbornene-catalyzed ordered reaction
sequence
Nicola Della Ca’a, Marco Fontanaa, Di Xua,b, Mirko Cremaschia, Riccardo Lucentinia, Zhi-Ming
Zhoub, Marta Catellania,* and Elena Mottia,*
marta.catellani@unipr.it, elena.motti@unipr.it
a Dipartimento di Chimica and CIRCC, Università di Parma, Parco Area delle Scienze, 17/A, I-43124 Parma, Italy
b R&D Centre for Pharmaceuticals, School of Chemical Engineering and the Environment, Beijing Institute of
Technology, Beijing 100081, PR China
Copies of 1H NMR and 13C NMR spectra

ACCEPTED MANUSCRIPT
3’-Hydroxymethyl-1,1’-biphenyl-2-carbaldehyde (6, R1, R2 = H, Table 3)

ACCEPTED MANUSCRIPT
2’-Hydroxymethyl-2-(2”-exo-norbornyl)-1,1’-biphenyl-3-carbaldehyde (7, R1,R2 = H, Table 3)

ACCEPTED MANUSCRIPT
3’-Hydroxymethyl-4,5’-dimethoxy-1,1’-biphenyl-2-carbaldehyde (6, R1 = H, R2= OMe, Table 3)

ACCEPTED MANUSCRIPT
2’-Hydroxymethyl-4’,5-dimethoxy-2-(2”-exo-norbornyl)-1,1’-biphenyl-3-carbaldehyde (7, R1 = H,
R2 = OMe, Table 3)

ACCEPTED MANUSCRIPT
5’-Hydroxymethyl-3,4,3’,4’-tetramethoxy-1,1’-biphenyl-2-carbaldehyde (6, R1, R2 = OMe, Table
3)

ACCEPTED MANUSCRIPT
2’-Hydroxymethyl-4,5,3’,4’-tetramethoxy-2-(2”-exo-norbornyl)-1,1’-biphenyl-3-carbaldehyde (7,
R1, R2 = OMe, Table 3)

ACCEPTED MANUSCRIPT
5’-Hydroxymethyl-4,3’-dicarbomethoxy-1,1’-biphenyl-2-carbaldehyde (6, R1 = H, R2 = CO2Me,
Table 3)

ACCEPTED MANUSCRIPT
2’-Hydroxymethyl-4’,5-dicarbomethoxy-2-(2”-exo-norbornyl)-1,1’-biphenyl-3-carbaldehyde (7, R1
= H, R2 = CO2Me, Table 3)

ACCEPTED MANUSCRIPT
3-Methoxy-2-(2”-exo-norbornyl)-1,1’-biphenyl-2’-carbaldehyde (9, Scheme 4)

ACCEPTED MANUSCRIPT
3’-Methoxy-[1,1’]-biphenyl-2-carbaldehyde (3ja, Scheme 4)

ACCEPTED MANUSCRIPT
5’-Methoxy-3’-methyl-2’-d-[1,1’]-biphenyl-2-carbaldehyde-formyl-d (10, Scheme 6)

ACCEPTED MANUSCRIPT
3,4,6-Trimethyl-6H- dibenzo[b,d]pyran (13la, R1, R2 = Me, R3 = H, R4 = Me, Table 7)

ACCEPTED MANUSCRIPT
1-(3’,4’-dimethyl-[1,1'-biphenyl]-2-yl)ethanone (12la, R1, R2 = Me, R3 = H, R4 = Me, Table 7)