Lewis acid-driven reaction pathways in synergistic cooperative catalysis over gold/palladium bimetallic nanoparticles for hydrogen autotransfer reaction between amide and alcohol

Article abstract of DOI:10.1016/S1872-2067(16)62483-X

Metal nanoparticle catalysts, especially gold and its bimetallic nanoparticle catalysts, have been widely used in organic transformations as powerful and green catalysts. The concept of employing two distinct catalysts in one reaction system, such as in cooperative and synergistic catalysis, is a powerful strategy in homogeneous catalysis. However, the adaption of such a strategy to metal nanoparticle catalysis is still under development. Recently, we have found that cooperative catalytic systems of gold/palladium bimetallic nanoparticles and Lewis acid can be used for the N-alkylation of primary amides through hydrogen autotransfer reaction between amide and alcohol. Herein, the results of a detailed investigation into the effects of Lewis acids on this hydrogen autotransfer reaction are reported. It was found that the choice of Lewis acid affected not only the reaction pathway leading to the desired product, but also other reaction pathways that produced several intermediates and by-products. Weak Lewis acids, such as alkaline-earth metal triflates, were found to be optimal for the desired N-alkylation of amides.

Full text of DOI:10.1016/S1872-2067(16)62483-X

Chinese Journal of Catalysis 37 (2016) 1662–1668
a v a i l a b l e a t w w w . s c i e n c e d i r e c t . c o m
j o u r n a l h o m e p a g e : w w w . e l s e v i e r . c o m / l o c a t e / c h n j c
Communication (Special Issue on Gold Catalysis)
Lewis acid‐driven reaction pathways in synergistic cooperative
catalysis over gold/palladium bimetallic nanoparticles for hydrogen
autotransfer reaction between amide and alcohol
Hiroyuki Miyamura, Satoshi Isshiki, Hyemin Min, Shū Kobayashi *
Department of Chemistry, School of Science, The University of Tokyo, Tokyo 113‐0033, Japan
A R T I C L E I N F O
A B S T R A C T
Article history:
Metal nanoparticle catalysts, especially gold and its bimetallic nanoparticle catalysts, have been
widely used in organic transformations as powerful and green catalysts. The concept of employing
two distinct catalysts in one reaction system, such as in cooperative and synergistic catalysis, is a
powerful strategy in homogeneous catalysis. However, the adaption of such a strategy to metal
nanoparticle catalysis is still under development. Recently, we have found that cooperative catalytic
systems of gold/palladium bimetallic nanoparticles and Lewis acid can be used for the N‐alkylation
of primary amides through hydrogen autotransfer reaction between amide and alcohol. Herein, the
results of a detailed investigation into the effects of Lewis acids on this hydrogen autotransfer reac‐
tion are reported. It was found that the choice of Lewis acid affected not only the reaction pathway
leading to the desired product, but also other reaction pathways that produced several intermedi‐
ates and by‐products. Weak Lewis acids, such as alkaline‐earth metal triflates, were found to be
optimal for the desired N‐alkylation of amides.
Received 14 April 2016
Accepted 7 June 2016
Published 5 October 2016
Keywords:
Gold
Palladium
Bimetallic nanoparticle
Lewis acid
Amide synthesis
Hydrogen autotransfer
© 2016, Dalian Institute of Chemical Physics, Chinese Academy of Sciences.
Published by Elsevier B.V. All rights reserved.
Metal nanoparticles have recently attracted much attention
as catalysts for organic synthesis because of their unique activi‐
ties and selectivities, which are derived from both the charac‐
teristic nature of their surfaces and their electronic structures
[1–11]. Among them, gold and its bimetallic nanoparticles have
been found to be excellent catalysts for a range of redox pro‐
cesses such as aerobic oxidation, hydrogenation, and hydrogen
transfer reactions [1–4,7,12–19].
We have developed a general strategy to encapsulate vari‐
ous kinds of single and bimetallic nanoparticles in polysty‐
rene‐based polymers with cross‐linking moieties by using a
strategy termed polymer incarceration (PI) [17,18,20]. Using
this methodology, we have prepared both single metal and
bimetallic nanoparticle catalysts [20–26] and applied these
unique catalytic systems to various organic transformations
including redox reactions [20,23,24,26–32], cooperative cataly‐
sis [27,33,34], multistep tandem processes [30,35,36], and
asymmetric transformations (Fig. 1) [37–39]. In these hetero‐
geneous catalysts, metal nanoparticles are stabilized by multi‐
ple and weak interactions between the ‐electrons of benzene
rings and the surface of the metal nanoparticles. This charac‐
teristic interaction results in high activity and increased ro‐
bustness of the catalysts, and suppresses leaching of metal na‐
noparticles and their aggregation.
* Corresponding author. Tel/Fax: +81‐3‐5841‐4790; E‐mail: shu_kobayashi@chem.s.u‐tokyo.ac.jp
This work was partially supported by a Grant‐in‐Aid for Science Research from the Japan Society for the Promotion of Science (JSPS), the Global COE
Program, the University of Tokyo, the Japan Science and Technology Agency (JST), and the Ministry of Education, Culture, Sports, Science and Tech‐
nology (MEXT, Japan).
DOI: 10.1016/S1872‐2067(16)62483‐X | http://www.sciencedirect.com/science/journal/18722067 | Chin. J. Catal., Vol. 37, No. 10, October 2016

Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
1663
Scheme 1. Preparation of the PI/CB‐Au/Pd catalyst.
Fig. 2. STEM and EDS images of the PI/CB‐Au/Pd catalyst.
alcohol in the presence of 1 mol% of PI/CB‐Au/Pd and 5 mol%
of Ba(OTf)2 gave moderate to excellent yields of desired prod‐
ucts with wide substrate scope (Scheme 2(a)). In addition,
PI/CB‐Au/Pd catalyst can be recovered and reused keeping
high activity with simple operation (Scheme 2(b)). Several
control experiments suggested that Lewis acids facilitate nu‐
cleophilic attack of a primary amide, which has much lower
nucleophilicity than the corresponding amine, and this is the
key to the success of this relatively challenging hydrogen auto‐
transfer reaction. In the proposed reaction pathways, multiple
reaction steps are elaborated and, in addition to the desired
product, various intermediates and side‐products are also
formed (Fig. 3). In this communication, we describe the effect of
Lewis acid on the complex reaction schemes in detail and dis‐
cuss the correlation between the nature of the Lewis acid and
the reaction pathway followed.
Fig. 1. Schematic image of the PI technique.
Hydrogen transfer/borrowing strategies are useful for
conducting both C–C and C–heteroatom bond‐formation reac‐
tions with high atom efficiency because these transformations
are redox‐neutral overall and no externally added oxidant or
reductant is required [40–45]. In addition to the various ho‐
mogeneous catalysts that have been developed for hydrogen
transfer/borrowing reactions, metal nanoparticles have also
been demonstrated to be effective catalysts for these transfor‐
mations [46,47]. The alkylation of amines by using alcohols
through hydrogen transfer/borrowing has been widely devel‐
oped; however, examples of the N‐alkylation of primary amides
are quite limited [48–53]. This could be because amides are
generally much less reactive than amines, so nucleophilic at‐
tack of a primary amide on an aldehyde generated in situ dur‐
ing the hydrogen transfer/borrowing process is difficult.
The strategy of utilizing two or more catalysts in one reac‐
tion system, so called synergistic or cooperative catalysis, is a
very powerful tool for catalysis because it can lead to a dra‐
matic reduction in the transition‐state energy compared with
those for single catalysts [54–56]. There are a number of syn‐
ergistic or cooperative catalysts that involve metal complexes
or organocatalysts; however, systems that are comprised of
heterogeneous metal nanoparticles are still developing fields
[27,33,34].
In a typical experiment, a Carousel® tube was charged with
benzamide (30.3 mg, 0.25 mmol), PI/CB‐Au/Pd (11.1 mg,
0.0025 mmol of Au) and a stirring bar. The carousel tube was
then placed in an argon‐filled glovebox. In the glovebox, addi‐
tives, if any, were added (e.g. Ca(OTf)2 (4.2 mg, 0.0125 mmol))
(a)
PI/CB-Au/Pd (1 mol%)
Ba(OTf)2 (5 mol%)
O
O
R1
OH
+
R1
N
R2
R2
1.0 eq.
NH2
H
toluene, reflux, Ar, 18 h
3.0 eq.
19 examples
44->99% yield
(b)
PI/CB-Au/Pd (1 mol%)
Ba(OTf)2 (5 mol%)
O
O
OH2
+
Ph
NH2
Ar
N
Ph
toluene, reflux, Ar
H
Recently, we developed synergistic cascade catalysts com‐
posed of a metal Lewis acid and gold/palladium (Au/Pd) bi‐
metallic nanoparticles (Scheme 1; Fig. 2) for the N‐alkylation of
a primary amide with a primary alcohol through a hydrogen
autotransfer mechanism. In this catalytic system, the choice of
Lewis acids is crucial for smooth catalytic turnover and selec‐
tion of reaction pathways [57]. After extensive optimization of
reaction conditions, we have found that using 3 equivalents of
2
3.0 eq.
1.0 eq.
Run
Yield (%)
1
>99
2
99
3
53
4–11a
95–99
a Recovered catalyst was heated at 170 °C for 5 h under air before run 4,
7, and 10.
Scheme 2. Optimized reaction conditions for substrate scope and re‐
covery & reuse of catalyst for N‐alkylation of primary amide [57].

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Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
Fig. 3. Expected reaction pathways followed during synergistic cooperative catalysis using Au/Pd bimetallic nanoparticles and Lewis acids.
O
PI/CB-Au/Pd (1 mol%)
Ba(OTf)2 (x mol%)
O
O
OH2
Ph
NH
O
+
Me
Ph
NH2
Ar
N
Ph Ar
O
Ar
Ar
Ar
N
Ph
toluene, reflux, Ar
H
1
2
3
4
H
4.0 eq.
1.0 eq.
Scheme 3. General scheme for kinetic investigations using various amount of Ba(OTf)2.
and the tube was sealed tightly with a septum. The septum was
also taped tightly to the tube and the tube was then removed
from the glovebox. 4‐Methylbenzyl alcohol (81.1 mg, 0.75
mmol) and toluene (0.5 mL) were added, and then the part of
the septum where the syringe needle went through was cov‐
ered with tape. The tube was then placed on a Carousel® (par‐
allel synthesiser from Radleys) that had been preheated to 150
°C and it was left to stir for 18 h, after which it was allowed to
cool to room temperature. Ethyl acetate was added to dilute the
mixture and the GC internal standard (dodecane) was added.
An aliquot was passed through Celite into a GC phial and the
clear solution was subjected to GC analysis.
Firstly, we examined reaction profiles of N‐alkylation of
amide through hydrogen autotransfer (Scheme 3) using 1
mol% of PI/CB‐Au/Pd and (0–5) mol% of Ba(OTf)2 in order to
confirm the synergy between Lewis acid and PI/CB‐Au/Pd
catalysts. In the presence of 5 mol% of Ba(OTf)2, we observed
clear induction period for the formation of desired product (2)
and ether (3) (Fig. 4). On the other hand, p‐tolualdehyde and
xylene (4) generated immediately after starting reaction. We
also found induction period for generation of N,N‐diamide (1)
and it was steady state intermediate during 0.5–3 h. Yield of
desired product reached over 90% at 6 h and further prolong‐
ing reaction to 18 h resulted in more consumption of
p‐tolualdehyde and alcohol and increase in amount of xylene
(4). When amount of Ba(OTf)2 was reduced to 2.5 mol% (Fig.
5), generation speed of desired product (2) and ether (3) de‐
creased dramatically especially at initial stage (0.5–3 h), while
initial production ratio of p‐tolualdehyde and xylene (4) was
almost same as the case using 5 mol% of Ba(OTf)2. When
amount of Ba(OTf)2 was further reduced to 1 mol% (Fig. 6),
longer induction periods (~2 h) for product (2) and ether (3)
were observed and concentration of N,N‐diamide (1) at steady
state decreased, while initial production ratio of p‐tolualdehyde
was almost same as the case using 5 mol% of Ba(OTf)2. When
Ba(OTf)2 was not used, very low production ratio for desired
product (2) was observed and only 30% yield was obtained at
18 h (Fig. 7). On the other hand, still similar production ratio of
(2)
(1)
product
N,N‐diamide
(2)
(1)
product
ether
N,N‐diamide
140
120
100
80
140
120
100
80
(3)
ether
4‐MeBnOH
p‐xylene
benzamide
benzamide
(3)
4‐MeBnOH
p‐tolualdehyde
p‐tolualdehyde
(4)
(4)
p‐xylene
60
60
40
40
20
20
0
0
0
2
4
6
8
10
12
14
16
18
20
0
2
4
6
8
10 12 14 16 18 20
Time (h)
Time (h)
Fig. 4. Reaction profile using 5 mol% of Ba(OTf)2.
Fig. 5. Reaction profile using 2.5 mol% of Ba(OTf)2.

Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
1665
Table 1
140
120
100
80
(2)
(1)
product
ether
N,N‐diamide
benzamide
Condensation between tolualdehyde and benzamide.
(3)
4‐MeBnOH
p‐tolualdehyde
p‐xylene
(4)
Entry
Lewis acid
Ba(OTf)2
Ca(OTf)2
Mg(OTf)2
Sc(OTf)3
Yb(OTf)3
Cu(OTf)2
Al(OTf)3
none
Yield 1 (%)
60
1
2
3
4
5
6
7
8
10
15
34
>99
>99
>99
>99
5
40
20
0
0
2
4
6
8
10
Time (h)
12
14
16
18
20
Fig. 6. Reaction profile using 1 mol% of Ba(OTf)2.
140
amide through hydrogen autotransfer. Although we have been
able to obtain quantitative yield of desired products (2) using 3
equivalents of benzylic alcohol, in this study we analyzed the
products and intermediates formed by using 1.5 equivalents of
4‐methyl benzyl alcohol as a starting material in order to em‐
phasize the difference in results and evaluated the reaction
pathways that were accelerated by Lewis acids. We examined
the use of a selection of metal Lewis acids (Li, Ca, Ba, Mg, Zn, Cu,
Fe, Sn, Ce, Sm, Sc, Bi, In, Hf, and Yb) as cations, and halides, sul‐
fate, triflate, hydroxide, and alkoxide as anions (Table 2).
120
100
80
60
40
20
0
product (2)
(3)
N,N‐diamide (1)
benzamide
p‐tolualdehyde
ether
4‐MeBnOH
p‐xylene (4)
It was assumed that the Lewis acid did not influence step A
significantly as we discussed in previous chapter. The other
steps are highly dependent on the type of Lewis acid employed,
with the most important feature of the Lewis acid being the
selective activation of either the aldehyde or amide [58]. In
Table 2, entries 1–6, the Lewis acids are thought to activate the
aldehyde selectively and either 3 step E or F, or both steps are
accelerated. As a result, the ether was obtained rather than the
N,N‐diamide 1 or the desired amide product 2. This tendency is
supported by reports that Bi(OTf)3, BiBr3, Cu(OTf)2, or In(OTf)3
can be used as catalysts or activators in hydroxymethylation or
reductive coupling reactions with aldehydes [59,60]. Some
alkali‐earth and rare‐earth metal (lanthanides) cations are
known to be effective catalysts for the activation of amides or
carbamates [61,62]. In entries 7–19, Lewis acids containing
these kinds of metals were used; in this case, although the de‐
sired product 2 was obtained selectively, a large amount of
xylene 4 was also formed. We concluded that both the Lewis
acidity and the basicity of the counteranion of these Lewis acids
were important factors that determined the rate of formation
of N,N‐diamide 1 or product amide 2 (steps C or D, or both
steps). At the same time, xylene 4 formation (step B) was also
strongly accelerated by using these Lewis acids. Reactions cat‐
alyzed by alkaline‐earth metal (Ca, Ba, and Mg) triflates,
showed particularly high selectivity toward formation of the
desired product (entries 7, 11, and 13). The Lewis acids shown
in entries 20–23 were too weak to form the product amide,
although the N,N‐diamide intermediate was generated (step C
was accelerated, but not step D). The “borrowed” hydrogen is
returned to the alcohols selectively and, as a result, relatively
high yields of the N,N‐diamide and xylene were obtained. The
alcohols are consumed in the formation of xylene and, ulti‐
0
2
4
6
8
10
12
14
16
18
20
Time (h)
Fig. 7. Reaction profile without Ba(OTf)2.
p‐tolualdehyde was observed at initial stage. Almost similar
production ratio of p‐tolualdehyde at initial stage regardless of
amount of Ba(OTf)2 clearly indicated that no participation of
Ba(OTf)2 in the step A (Fig. 3). On the other hand, concentration
of p‐tolualdehyde at middle stage, at which N,N‐diamide (1)
was observed as steady state intermediate and concentration
of desired product (2) increased constantly, as the amount of
Ba(OTf)2 increased. These paradoxical results were resulted
from the acceleration of catalytic turnover of PI/CB‐Au/Pd
through synergistic cooperation of Lewis acids, that will be
discussed later.
Condensation between p‐tolualdehyde and benzamide was
investigated in the presence of various Lewis acids without
PI/CB‐Au/Pd (Table 1). Reactions were conducted using 1
mol% of Lewis acids for 1 h. Surprisingly, the optimized Lewis
acid, Ba(OTf)2, in previous study did not accelerate condensa‐
tion so much as well as other alkaline earth metal triflates (en‐
tries 1–3 vs. 8). As we expected, stronger Lewis acids, such as
Sc and Yb triflates, showed dramatic acceleration of the con‐
densation (entries 4–7). It was clear that Lewis acids play very
important role in step C even in the absence of PI/CB‐Au/Pd
(Fig. 3).
Next, we moved on the investigation of effect of various
Lewis acids on the reactivity and selectivity in N‐alkylation of

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Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
formation of the N,N‐diamide (step C) is suppressed. At the
Table 2
same time, dehydrogenation from the alcohol to the aldehyde
(step A) can be accelerated and generated hydrogen is con‐
sumed for reduction of the alcohol to xylene (step B). A similar
tendency to produce very little of the desired product was ob‐
served in our previous trial when basic molecular sieves MS3A
or 4A was used as an additive [57].
Synergistic cooperative effect between Au/Pd nanoparticle
catalyst and Lewis acid catalyst is shown in their reaction
mechanism (Fig. 3). The reaction is initiated by the accumula‐
tion of the aldehyde (step A) and it results in the formation of
xylene accompanying consumption of sacrificial alcohols (step
B). Then, aldehyde reacts with primary amide or alcohol to
form hydrogen acceptors such as N,N‐diamide (step C) or oxo‐
carbenium ion (step E), and hydrogen returning to these hy‐
drogen acceptors affords desired amide product (step D) or
ether as side product (step F).
Large amount of aldehyde was observed at the early stage of
the reaction regardless of the presence of Lewis acids, while the
xylene was steadily formed. Aldehyde and xylene were formed
even in the reaction without Lewis acid (Fig. 7; in this case,
Ba(OTf)2) through disproportionation‐like reaction (Step A and
B). Yield of the desired product was very low and N,N‐diamide
intermediate was not detected in the absence of Lewis acid
(Fig. 7). However, when Lewis acid was used, the rate of the
formation of the desired product, xylene and ether was in‐
creased and this rate was correlated with the amount of
Ba(OTf)2 because of Lewis acid acceleration (Figs. 4–6). In addi‐
tion, we could see N,N‐diamide intermediate in a certain con‐
centration at steady state.
This Lewis acid acceleration also made alcohol consumption
much faster (steps A and B). In terms of the yield and rate of
desired product formation, swift increase in the yield of desired
product was observed after several times (induction period),
and this period was almost corresponded to that of steady
amount of N,N‐diamide. During this period, the amount of al‐
dehyde was significantly increased and reached to steady state;
it implies that accumulation of aldehyde is needed for initiation
of the desired product formation.
Effect of Lewis acids on the N‐alkylation of a primary amide through
hydrogen autotransfer.
Yield (%)
Entry
Lewis acid
1
0
2
4
4
4
7
2
3
4
6
trace
8
8
8
1
2
3
4
Bi(OTf)3
BiBr3
30
12
22
33
31
36
50
32
50
50
50
32
In(OTf)3
Sn(OTf)2
Cu(OTf)2
Cu(OTf)
Ba(OTf)2
BaSO4
Yb(OTf)3
Sc(OTf)3
Mg(OTf)2
Li(OTf)
Ca(OTf)2
CaSO4
Bi2(SO4)3
4BiNO3(OH)2
BiO(OH)
ZnCl2
5
6
14
7
8
9
10
11
12
13
14
15
16
2
0
10
12
4
72
40
50
44
67
45
59
37
40
42
2
1
7
6
2
2
2
1
2
2
29
33
42
43
30
30
28
28
41
22
0
2
0
5
4
17
18
19
20
21
22
23
24
25
26
27
28
29
21
6
42
58
47
26
2
1
1
47
41
24
25
47
60
58
43
42
43
33
30
93
ZnSO4
CuSO4
16
18
21
40
39
20
19
19
5
11
2
BiF3
ZnF2
5
4
In2(SO4)3
Fe2(SO4)3
Ce(OTf)4
Sm(OTf)3
Hf(OTf)4
Zn(OTf)2
Al(OTf)3
Zn(OtBu)2
14
16
25
24
25
22
16
2
5
11
11
11
21
25
23
4
14
* Yield was calculated based on the amount of benzamide used (Yield =
(mmol of compound)/(mmol of used benzamide)).
In this reaction mechanism, Au/Pd nanoparticle catalyst
played important role in hydrogen transfer from alcohol (step
A) to the various hydrogen acceptors (steps F and D), on the
other hand, Lewis acid mainly worked in N,N‐diamide for‐
mation, carbonium cation formation (steps C and E) and hy‐
drogen returning (steps F and D). Those steps are intimately
connected; in hydrogen returning step (steps F and D) (even
there is competition between desired reaction pathway and
side reaction pathway), the rate of these steps would be affect‐
ed by the amount or the formation rate of hydrogen acceptors,
which is catalyzed by Lewis acids. Faster hydrogen returning
would accelerate the Au/Pd catalyst turnover and it results in
production of more aldehyde, then successive formation of
hydrogen acceptors would occur. Formation of xylene (step B)
is also highly affected by the presence of Lewis acids indirectly.
High Au/Pd nanoparticle catalyst turnover, which depends on
the generation speed of hydrogen accepters catalyzed by Lewis
acids, would also accelerate step B. As a result, acceleration of
mately, no alcohols remain for reduction of the N,N‐diamide
intermediate and for aldehyde formation to proceed in the next
catalytic cycle. In entries 24–26, relatively high yields of the
N,N‐diamide and xylene were also observed, but the yields of
the amide product and the ether were also high compared with
the results presented in entries 20–23. We suggest that this is
probably because of too strong Lewis acidity [63]; they activate
both aldehyde and amide moieties in all steps, thereby elimi‐
nating the specific selectivity. From the results, however, it
seems that the formation of xylene (step B) is easier than the
other steps. In entries 27–28, almost no selectivity was ob‐
served; however, less acceleration for the formation of
N,N‐diamide (step C or D) and greater acceleration for for‐
mation of the ether (step E or B) was observed compared with
the results presented in entries 24–26. In the presence of a
strong basic cocatalyst, the desired pathway did not proceed
and only step B was accelerated (entry 29). Under strongly
basic conditions, activation of the amide is difficult and the

Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
1667
various steps by Lewis acids would bring faster catalytic turn‐
References
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alcohol selectively. The interesting findings concerning Lewis
acid‐driven reaction pathways reported in this study provide
new possibilities and directions for the further design of coop‐
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Graphical Abstract
Chin. J. Catal., 2016, 37: 1662–1668 doi: 10.1016/S1872‐2067(16)62483‐X
Lewis acid‐driven reaction pathways in synergistic cooperative
catalysis over gold/palladium bimetallic nanoparticles for
hydrogen autotransfer reaction between amide and alcohol
Hiroyuki Miyamura, Satoshi Isshiki, Hyemin Min, Shū Kobayashi *
The University of Tokyo, Japan
The choice of Lewis acid determines the course of N‐alkylation of a primary
amide through hydrogen autotransfer reaction catalyzed by cooperative
catalytic systems composed of Au/Pd bimetallic nanoparticles and Lewis
acid, and directs the course of the reaction towards the desired product or
by‐product.

1668
Hiroyuki Miyamura et al. / Chinese Journal of Catalysis 37 (2016) 1662–1668
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