Ligand effects on decarbonylation of palladium-acyl complexes

Ligand E ﬀ ects on Decarbonylation of Palladium-Acyl Complexes

Article

Tedd C. Wiessner, Samuel Asiedu Fosu, Ri ﬀ at Parveen, Nigam P. Rath, Bess Vlaisavljevich,*

and William B. Tolman*

Cite This: https://dx.doi.org/10.1021/acs.organomet.0c00584

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sı Supporting Information

ABSTRACT: The inﬂuences of perturbations of supporting phosphine

ligands on the dehydrative decarbonylation of (L )Pd (Cl)-hydro-

cinnamoyl complexes (L = P Bu , n = 1; L = PPh , n = 2; L = dppe, n

1) to yield styrene were studied through combined experiment and

theory. Abstraction of chloride from the complexes by silver and zinc

salts, as well as sodium tetrakis[3,5-bis(triﬂuoromethyl)phenyl]borate,

enhanced the eﬃciency of styrene formation, according to the following

trend in L: P Bu > dppe > PPh . DFT calculations corroborated the

experimental ﬁndings and provided insights into the ligand inﬂuences on

reaction step barriers and transition state structures. Key ﬁndings include

the following: a stable intermediate forms after chloride abstraction, from

which β-hydride elimination is most aﬀected by ligand choice, the low

coordination number for the P Bu case lowers reaction barriers for all

steps, and the trans disposition of two ligands for L = PPh contributes to

the low eﬃciency for styrene production in that case.

INTRODUCTION

Scheme 1. Plausible Catalytic Cycle for the Decarbonylative

Dehydrogenation of Fatty Acid Derivatives

■

Linear α-oleﬁns (LAOs) are important commodity chemicals

typically derived from petroleum feedstocks through ethylene

oligomerization, generated in even-numbered chain lengths

following a Flory−Schulz distribution. An attractive, “green”

alternative is the dehydrative decarbonylation of biorenewable

carboxylic acids, particularly fatty acid derivatives. Catalytic

conversions of carboxylic acids to oleﬁns usually requires

activation of the acid, as illustrated by examples using p-

nitrophenyl esters, anhydrides, or acyl halides. Catalysts

5d,7

comprising complexes of Rh,

Ru, Ir, Fe, Ni, and, most

have been developed. Photoredox methods

undergo a diﬀerent, single-electron pathway for the synthesis of

,5,11

commonly, Pd

oleﬁns directly from the carboxylic acid.

The mechanism for the catalytic dehydrative decarbon-

ylation of carboxylic acid derivatives is generally thought to

M denotes a metal, L denotes the ligand with n being the number of

ligands.

proceed as shown in Scheme 1. According to this pathway, a

low-valent metal, M, undergoes oxidative addition into the acyl

C−X bond of the carboxylic acid derivative to form

intermediate B, which subsequently undergoes deinsertion to

form metal−alkyl complex C. The oleﬁn complex D forms via

β-hydride elimination. It ejects the product oleﬁn and

reductively eliminates HX to regenerate the active catalyst.

activating group (X) likely aﬀect the kinetics, thermodynamics,

and structures of the intermediates, with the dissection of these

inﬂuences being important for future catalyst design.

Received: September 1, 2020

Previous computational studies indicated that oxidative

addition is not rate-determining for appropriately activating

X groups and that the greatest barriers arise along the

deinsertion and β-hydride elimination path (B → D). While

this mechanism is useful as a general framework, diﬀerences

among the supporting ligands (L), metal ion (M), and

XXXX American Chemical Society

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

With the overarching aim of understanding catalyst

structural eﬀects on catalytic activity, we chose to focus on

the speciﬁc eﬀects of varying the supporting ligands in Pd

complexes on the deinsertion and β-hydride elimination steps.

Toward this end, we chose to examine the reactivity of Pd-acyl

complexes of type B, derived speciﬁcally from hydrocinnamoyl

chloride, because styrene would be the only possible oleﬁn

product (i.e., chain walking is avoided). We further focused on

complexes bound to ligands P Bu , PPh , and dppe (1,2-

bis(diphenylphosphino)ethane)) in order to evaluate steric

eﬀects on the coordination environment and reactivity. The

bulky P Bu has a large cone angle (θ) of 182° and a buried

Figure 1. Representations of the X-ray crystal structures of 2 and 3

showing all non-hydrogen atoms as 50% thermal ellipsoids. Selected

bond distances (Å): 2, Pd−C(1) 1.983(2), Pd−P(1) 2.3486(5), Pd−

P(2) 2.3393(5), Pd−Cl(1) 2.4291(5), O(1)−C(1) 1.191(2); 3, Pd−

C(1) 2.033(2), Pd−P(1) 2.3956(5), Pd−P(2) 2.2331(5), Pd−Cl(1)

volume (V_%_b_u_r) of 38.1% (measured by R P-AuCl), which has

been reported to induce a three-coordinate geometry in Pd-

acyl species. On the other hand, PPh is signiﬁcantly smaller

(

θ = 145°, V_%_b_u_r= 29.9% on AuCl), forming four-coordinate

trans-phosphine complexes on Pd. The ligand dppe (θ =

18.6°, V_%_b_u_r= 51.4% on PdCl or 29.2% on (AuCl) ) is

2.3693(5), O(1)−C(1) 1.201(3).

similar in size to two PPh ligands but is constrained to adopt a

moiety in 3 has an intermediate eﬀect, and the absence of a

trans ligand in 1 results in the most downﬁeld peaks.

The complexes 1−3 are stable at room temperature, even in

air for several days. In initial studies of their reactivity,

cis-phosphine geometry. With the aim of evaluating how

these diﬀerences aﬀected the deinsertion and β-hydride

elimination steps, we targeted Pd-hydrocinnamoyl complexes

for synthesis and reactivity studies, with experimental studies

informed by theory. The ﬁndings we report herein reveal clear

inﬂuences of the phosphine structure on the mechanism of

deinsertion and β-hydride elimination, with possible implica-

tions for future catalyst design.

solutions of the complexes in CH CN or THF were heated (T

40−65 °C) in attempts to induce decarbonylation and

identify intermediates. In every case, the starting material

decayed gradually (12−24 h) and some styrene was observed

(

most eﬀectively by 1, 40 °C for 12 h, Figure S1). However,

product mixtures formed, and the components were

challenging to identify ( H NMR spectroscopy, Supporting

RESULTS AND DISCUSSION

Experiment. The Pd-hydrocinnamoyl complexes 1−3 were

prepared as shown in Scheme 2. Compound 1 was identiﬁed

■

Information). Hypothesizing that initial decarbonylation would

be facilitated by coordinative unsaturation at the metal center

(

supported by density functional theory (DFT) results

Scheme 2. Syntheses of 1−3

described below), we sought to remove the chloride ligands

in the complexes by treating them with silver and zinc salts, as

well as NaBAr^F(sodium tetrakis[3,5-bis(triﬂuoromethyl)-

phenyl]borate; Table 1).

Table 1. Conversions of Pd-Acyl Complexes to Styrene

conversion (%)

additive

by a comparison of its H and C{ H} NMR spectra and X-

AgBF₄

>99

ray crystal structure with data previously reported; 2 and 3

NaBAr^F

ZnCl₂

were characterized by H, C{ H}, and P NMR spectros-

copy and X-ray crystallography (Figure 1). While 1 adopts a

slightly distorted T-shaped geometry with the phosphine

Zn(OAc)₂

ZnO

ligand trans to chloride, 2 and 3 are square planar with trans

_a_n_d_c_i_s_p_h_o_s_p_h_i_n_e_l_i_g_a_n_d_s_,_r_e_s_p_e_c_t_i_v_e_l_y_.31P NMR spectra are

D PT

Determined by in situ H NMR spectroscopy. D PT = 1,3-

consistent with retention of the solid-state coordination

environments in solution, as 2 exhibits only one peak at 19.6

ppm for two equivalent phosphine ligands and 3 shows two

coupled doublets, indicating inequivalent P atoms in a cis

geometry (37.7 and 20.5 ppm, J = 44 Hz). Comparison of the

diisopropyl-2-thiourea. Reactions of 1 were performed in acetoni-

trile-d₃. Cationic complex also formed. 3-Phenylpropanal also

observed.

hydrocinnamoyl methylene peaks in H NMR spectra for the

In the case of 1, reactions with silver salts (e.g., AgBF ) were

three complexes shows a trend in δ of 2 (1.51/2.19 ppm) < 3

complete within seconds, as noted by the rapid precipitation of

AgCl, formation of a black precipitate (presumably Pd black),

full consumption of the starting material, and quantitative

(

2.43/2.76 ppm) < 1 (2.89/3.54 ppm) that we attribute to

trans inﬂuences that may be important in the reactivity of the

complexes (vide infra). Thus, a trans chloride in 2 induces the

conversion to styrene ( H NMR). Reactions with NaBAr were

most upﬁeld chemical shift, a trans-PRPh (R = methylene)

slower, taking minutes to hours for full consumption of 1

Organometallics XXXX, XXX, XXX−XXX

Organometallics

Article

depending on the conditions, and were amenable to kinetic

analysis (vide infra). Reactions with zinc salts also aﬀorded

styrene, albeit typically at rates slower than the reactions with

silver reagents and not always as cleanly. Thus, treatment of 1

with and activate carbonyl compounds, induces consumption

of 1 to generate styrene, albeit in a modest 64% yield after 22 h

with the formation of side products that could not be easily

identiﬁed.

in acetonitrile with ZnCl led to quantitative styrene formation

within seconds, even when the reaction was performed with

In contrast to the reactions of 1, treatment of 2 with silver

and zinc salts and NaBAr^Funder the same conditions

produced very little styrene (<10%). Instead, a new species

substoichiometric amounts (33%), but Zn(OAc) and ZnO

produced styrene in only 77% and 24% yields, respectively,

after 22 h.

was observed by H NMR spectroscopy that we assign as the

cationic product of substitution of chloride by CH CN, 2 .

Monitoring of reactions of 1 and NaBAr by H NMR

spectroscopy revealed the disappearance of the peaks

associated with 1 concomitant with formation of styrene and

The species exhibits peaks in the H NMR spectrum similar to

those of 2, except for a slight downﬁeld shift of the methylene

protons of the hydrocinnamoyl ligand. We conclusively

identiﬁed 2 by isolating it as either its BF or SbF₆⁻salt as

−

growth of a doublet attributed to the phosphonium HP Bu

Figure S4 ). No other species were observed, implying that

a white solid and obtaining the X-ray crystal structure for the

latter case (Figure 2 ). The complex is square planar, with two

halide abstraction is rate-determining and all subsequent steps

are facile (deinsertion, β-hydride elimination). Consistent with

this conclusion and a ﬁrst-order dependence on 1, a plot of

ln[1] vs time where [NaBAr ] = 5.6 × 10 M and [1] = 1.3

−2

−

10 M is linear (Chart 1a). Performing the reaction at

Chart 1. (a) Selected Example of a Kinetic Plot for the

Reaction between 1 and NaBAr in Acetonitrile-d₃and (b)

Plot of k_o_b_s(Average of Triplicate Measurements; See

Figure S5) vs [NaBAr ], Where [Pd-acyl] = 0.013 M

Figure 2. Representation of the X-ray crystal structure of 2(SbF₆)

showing all non-hydrogen atoms as 50% thermal ellipsoids and the

SbF counterion omitted for clarity. Selected bond distances (Å):

Pd−C(1) 1.9915(19), Pd−N(1) 2.1606(17), Pd−P(1) 2.3513(5),

Pd−P(2) 2.3548(5), O(1)−C(1) 1.199(2).

trans-PPh ligands and an acetonitrile molecule replacing the

−

chloride ligand found in 2; a single SbF₆counterion is present

(

not shown), consistent with a monocationic Pd(II) species.

The isolation of 2⁺indicates that decarbonylation is

signiﬁcantly slowed relative to 1. Consistent with this

conclusion, while thermolysis of 1 (65 °C, CD CN, 12 h)

quantitatively aﬀorded styrene, heating 2(BF ) under identical

conditions produced styrene in only a 37% yield with 16% of

(BF ) remaining. Treatment of 2(BF ) with ZnCl (1.5

equiv) in CH Cl /CH CN (9/1) produced a small amount of

styrene (10% yield). This result is consistent with some

decarbonylation promoted by Lewis acid coordination to the

carbonyl in the cationic complex. Overall, the sluggish

decarbonylation of 2 contrasts with the reactivity observed

for 1, pointing toward signiﬁcant diﬀerences in the accessibility

of the necessary transition state geometry imposed by the

diﬀerent phosphine ligands (vide infra).

Finally, anticipating that in 3 a cis arrangement of the acyl

and chloride ligands might lead to enhanced reactivity upon

chloride removal, we examined the reactivity of 3 with silver

1] = 1.3 × 10 M, [NaBAr ] = 5.6 × 10 M, k_o_b_s₌₃_.₁₁_×₁₀−3

0 0

1 2

−2

[

−

min , R = 0.995. The indicated linear ﬁt has the slope 0.184 M

min and intercept −7.7 × 10 M; R = 0.953.

−

−4

various concentrations of NaBAr (>[1]) and plotting versus

the observed rate constants also yield a linear ﬁt, consistent

salts. Addition of 1.5 equiv of AgBF to a solution of 3 in

with a ﬁrst-order dependence on NaBAr (Chart 1b). Taken

CD Cl /CD CN (9/1) revealed the formation of styrene

together, the data are consistent with rate = k[1][NaBAr ],

(18%), 3-phenylpropanal (33%), and a new species assigned as

indicative of rate-determining halide abstraction.

4 (39%; Scheme 3). This assignment was based on H,

While the results of the reactions of 1 with silver and zinc

COSY, C{ H}, and P NMR spectroscopy (Figure S9).

Attempts to isolate 4 by ﬁltering the reaction mixture into

salts and NaBAr suggest that CO deinsertion is activated by

the removal of chloride, it is also possible, particularly in the

case of the zinc salts, that deinsertion is promoted by binding

of the Lewis acid to the carbonyl group. Indeed, 1,3-

diisopropyl-2-thiourea, which is known to hydrogen bond

diethyl ether at −35 °C led to a yellow solid that exhibited the

same NMR spectra when it was dissolved in CD Cl , but when

it was dissolved in CD CN peaks analogous to those assigned

to 2 were observed, leading to an assignment as 3 that we

Organometallics XXXX, XXX, XXX−XXX

Organometallics

transition state structure to maintain a stable four-coordinate

Article

Scheme 3. Halide Abstraction Reactions of 3

Theory. In order to gain insight into the reactivity

diﬀerences observed experimentally, the structures of 1−3

and their dehydrogenative decarbonylation reactions were

explored by DFT calculations (computational details are given

in the Supporting Information ). We ﬁrst examined the

decarbonylation pathways via thermolysis. The CO deinsertion

step for 1 proceeds via a transition state with a free energy

barrier of 22.8 kcal/mol (Figure 3). The equivalent barriers for

2 and 3 are 33.1 and 28.9 kcal/mol, respectively. The lower

barrier calculated for 1 is consistent with the experimental

observation that upon heating 1 is most eﬀective at producing

styrene, albeit slowly.

Product mixtures are dependent on the solvent conditions. L is

postulated to be acetonitrile, and L′ is postulated to be carbon

monoxide or an empty coordination site, blocked by the methyl group

of the complex, perhaps stabilized by β-agostic interactions.

Next, the decarbonylation process was studied including

prior halide abstraction. The data reported in the energy proﬁle

(

Figure 3) involve Ag ions as the halide-abstracting agent

surmise is eﬀectively trapped by the solvent prior to

(these results are compared to those obtained using Na ions

in Figure S11 ). If chloride is abstracted using Ag followed by

decarbonylation. Curious if 4 could be an intermediate in

styrene production or if longer reaction times would lead to

_g_r_e_a_t_e_r_y_i_e_l_d_s_,_w_e_t _r _e _a _t _e _d ₃ _w _i _t _h _N _a _B _A _rF (1.5 equiv) in

explicit solvation of the Pd center by acetonitrile (ΔG = −1.0

kcal/mol), the free energy barrier for the CO deinsertion step

CD Cl /CD CN (9/1) (Figure S10). The reaction yielded

⧧

for 1 is lowered by 8.0 kcal/mol to ΔG = 14.8 kcal/mol

styrene (14%), aldehyde (30%), ethylbenzene (6%), and 4

46%), with the concentration of styrene and aldehyde

(

Figure 3). If the CH CN molecule is not explicitly

(

⧧

coordinated to Pd, the energy barrier is higher (ΔG = 16.5

kcal/mol).

products remaining constant after 12 h as 4 gradually decayed

to more ethylbenzene and there was no further increase in

styrene concentration. From these results we conclude that 3 is

more prone to decarbonylation than 2 but that the subsequent

reactions of the initial Pd-ethylbenzene complex are

complicated by reversible chain walking and the possible

intermediacy of a hydride species that would be responsible for

Both 2 (L = PPh ) and 3 (L = dppe) undergo CO

deinsertion reactions similar to that of 1 (L = P Bu ; Figure

). A similar amount of free energy is required in the bond-

making and -breaking processes in the transition state

⧧

structures for all three ligands (ΔG = 12.1, 11.3, and 11.0

aldehyde and ethylbenzene formation. The observed

increased tendency for decarbonylation is consistent with

reports of bidentate ligands facilitating decarbonylation in

decarbonylative cross couplings, whereas monodentate ligands

kcal/mol, respectively). However, coordination by acetonitrile

after chloride abstraction in 1 produces a slightly unstable

intermediate, which subsequently undergoes CO deinsertion.

Explicit solvation facilitates the reaction by allowing the

typically do not.

Figure 3. DFT computed reaction mechanism for Pd-catalyzed decarbonylation of 3-Phenylpropionyl chloride. Asterisks indicate the coordination

of an explicit acetonitrile (solvent) molecule. When CO is shown in gray, it is only coordinated in the black (P Bu ) pathway.

Organometallics XXXX, XXX, XXX−XXX

Organometallics

The Supporting Information is available free of charge at

Article

geometry at the Pd(II) center (Figure 4). On the other hand,

in complexes 2 and 3 , the most favorable transition state

(9.5 kcal/mol) in comparison to the values of 16.9 and 16.3

kcal/mol for the cases with PPh and dppe, respectively

(

Figure 3 and Schemes S13 and S14). This calculated trend

aligns with that seen by experiment, insofar as reactions

beginning with 1 produce styrene rapidly and quantitatively,

while 2 and 3 produce smaller yields of styrene. Although

solvation stabilizes CO deinsertion when P Bu is used, β-

hydride elimination is more favorable without explicit

solvation, which allows for a planar, four-coordinate geometry

to be maintained in the transition state wherein P Bu and CO

occupy cis positions. Despite the analogous PPh and dppe TS

structures having two phosphine groups coordinating to the

metal, the most favorable pathways also maintain a four-

coordinate Pd center since CO is decoordinated prior to β-

hydride elimination.

Overall, the calculations show that β-hydride elimination is

the rate-determining transition state (RDTS), deﬁned by the

highest energy transition state, for PPh3 and dppe. Addition-

ally, the presence of the stable halide elimination product for 2

and 3 signiﬁcantly increases the energy required to form

styrene and is not captured by the RDTS alone. The barriers

from this determining intermediate to the highest transition

state are 14.8, 30.9, and 27.9 kcal/mol for 1−3, respectively.

Figure 4. Deinsertion and β-hydride elimination optimized transition

state geometries for the pathways with the (a) P Bu and (b) PPh

ligands. Bond distances are given in Å and angles in degrees.

Hydrogen atoms not involved in β-hydride elimination are excluded

for clarity. Color code: P, blue; Pd, magenta; C, gray; O, red; N, teal.

structures are not solvated, since they are already four-

coordinate. The stability of the cationic intermediates 2 (ΔG

−12.2 kcal/mol) and 3 (ΔG = −12.1 kcal/mol) leads to

CONCLUSION

higher barriers for CO deinsertion of 23.1 and 21.3 kcal/mol,

respectively. Thus, while for 1 CO deinsertion is signiﬁcantly

hastened after halide abstraction relative to direct thermolysis,

for both 2 and 3 the two routes have similarly high barriers.

Further insight into the CO deinsertion process comes from

an analysis of the calculated transition state geometries. The

■

The dehydrative decarbonylation of (L )Pd (Cl)-hydrocinna-

moyl complexes (L = P Bu , n = 1; L = PPh , n = 2; L = dppe,

n = 1) was evaluated through experiment and theory with the

primary aim of understanding how changes in the nature of the

supporting phosphine ligand(s) inﬂuences the eﬃciency of

styrene formation and the energetics of the proposed reaction

respective transition states have P−Pd−C angles ranging from

69.2° with P Bu to 159.0° with PPh (Figure 4 and Figure

steps. Removal of the chloride ligand was found to enhance the

S12 ). The structure with P Bu has the shortest distance for the

production of styrene, with the complex of P Bu being the

newly formed Pd−C bond (2.25 Å), signifying stronger bonds

that stabilize the transition state structure. For the dppe

transition state (Figure S12), the P−Pd−C angle is 167.6° and

most eﬃcient. A solvento intermediate resulting from chloride

abstraction was structurally characterized for the complex of

PPh , and a related species was implicated on the basis of

the Pd−C bond distance is 2.28 Å. We surmise that the

NMR spectroscopy for the complex of dppe. DFT calculations

revealed β-hydride elimination from a stable intermediate

formed upon halide abstraction to be rate-determining for the

presence of a single P Bu ligand results in more favorable CO

deinsertion because of a relative lack of destabilizing steric

eﬀects. Also, in the CO deinsertion for the case of PPh , the

overall dehydrative decarbonylation. The barrier heights for

trans phosphine ligands must rotate to the cis position in the

transition state, and this requires 4.2 kcal/mol. We speculate

that steric eﬀects associated with the cis arrangement further

add to the energetic cost for CO deinsertion in this case

this step and the CO deinsertion step followed the trend P Bu

dppe < PPh , consistent with the experimentally observed

dependence of styrene production eﬃciency on the supporting

ligand (P Bu > dppe > PPh ). A key overall conclusion is that

(Scheme S8 ). For the case of the bidentate dppe ligand, the

coordinative desaturation through chloride removal and use of

trans arrangement is inaccessible, and the transition state

the highly sterically hindered P Bu greatly facilitate

exhibits steric characteristics that fall between those of P Bu

dehydrative decarbonylation. In addition, the enforcement of

a cis disposition of phosphine donors in dppe is beneﬁcial

and PPh . The CO deinsertion products are ∼10 kcal/mol

lower in energy than the TS barriers.

relative to the complex comprising PPh ligands. We hope that

The ﬁndings from the above analysis are in agreement with

these notions determined through a study of a particular Pd-

based test system will inform future eﬀorts to design new

catalysts for the generation of oleﬁns from bioderived

carboxylic acids.

the results of other studies. For example, it was observed that

PPh ligands decoordinate from a Pd catalyst during the

decarbonylative dehydration of butanoic acid to maintain four-

coordinate complexes, while the ligand remains coordinated to

13b

the less active Rh analogue.

Also, in an analysis of the

ASSOCIATED CONTENT

sı Supporting Information

■

turnover-limiting step in the formation of styrene from

hydrocinnamic acid by a Pd catalyst with a PPh ligand, it

https://pubs.acs.org/doi/10.1021/acs.organomet.0c00584.

was observed that the four-coordinate transition state

structures are more stable than the ﬁve-coordinate structur-

es.

Furthermore, the use of a bulkier phosphine was

Cartesian coordinates (XYZ )

predicted to lower the barrier by ∼10 kcal/mol.

Experimental and computational details and spectra

(PDF )

Turning next to the β-hydride elimination step, we ﬁnd that

the transition state with P Bu has the lowest energy barrier

Organometallics XXXX, XXX, XXX−XXX

Organometallics

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AUTHOR INFORMATION

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Corresponding Authors

Bess Vlaisavljevich − University of South Dakota, Vermillion,

South Dakota 57069, United States; orcid.org/0000-

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William B. Tolman − Department of Chemistry and Center

for Sustainable Polymers, Washington University in St. Louis,

St. Louis, Missouri 63130-4899, United States; orcid.org/

000-0002-2243-6409 ; Email: wbtolman@wustl.edu

Authors

Tedd C. Wiessner − Department of Chemistry and Center for

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Vermillion, South Dakota 57069, United States;

orcid.org/0000-0002-7816-094X

Riﬀat Parveen − University of South Dakota, Vermillion,

South Dakota 57069, United States; orcid.org/0000-

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Isomerization-Decarboxylation for Converting Alkenoic Fatty Acids

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Schimler, S. D.; Mitchell, L. A.; Wilborn, E. G.; John, A.; Hogan, L.

T.; Benson, B.; LaPointe, A. M.; Tolman, W. B. Dual-Catalytic

Decarbonylation of Fatty Acid Methyl Esters to Form Olefins. Chem.

Commun. 2018, 54, 7669−7672.

003-4941-7512

Nigam P. Rath − Department of Chemistry and Biochemistry

and Center for Nanoscience, University of MissouriSt. Louis,

St. Louis, Missouri 63121, United States

Complete contact information is available at:

https://pubs.acs.org/10.1021/acs.organomet.0c00584

(9) (a) Ternel, J.; Lebarbe, T.; Monflier, E.; Hapiot, F. Catalytic

Decarbonylation of Biosourced Substrates. ChemSusChem 2015, 8,

1585−1592. (b) Maetani, S.; Fukuyama, T.; Suzuki, N.; Ishihara, D.;

Ryu, I. Efficient Iridium-Catalyzed Decarbonylation Reaction of

Aliphatic Carboxylic Acids Leading to Internal or Terminal Alkenes.

Organometallics 2011, 30, 1389−1394.

Funding

This work was supported by the NSF Center for Sustainable

Polymers, a NSF Center for Chemical Innovation (CHE-

901635). X-ray diﬀraction data were collected using

(10) Maetani, S.; Fukuyama, T.; Suzuki, N.; Ishihara, D.; Ryu, I.

diﬀractometers acquired through NSF-MRI Award No.

CHE-1827756. Computations were performed on high

performance computing systems at the University of South

Dakota, funded by NSF Award No. CHE-1626516. Mass

spectrometry data were collected at the Washington University

NIGMS Biomedical Mass Spectrometry Resource supported

by NIH grants 5P41GM103422 and R24GM136766.

Iron-Catalyzed Decarbonylation Reaction of Aliphatic Carboxylic

Acids Leading to α -Olefins. Chem. Commun. 2012 , 48 , 2552 −2554.

(11) (a) Gooßen, L. J.; Rodríguez, N. A Mild and Efficient Protocol

for the Conversion of Carboxylic Acids to Olefins by a Catalytic

Decarbonylative Elimination Reaction. Chem. Commun. 2004, 4,

724−725. (b) Liu, Y.; Kim, K. E.; Herbert, M. B.; Fedorov, A.;

Grubbs, R. H.; Stoltz, B. M. Palladium-Catalyzed Decarbonylative

Dehydration of Fatty Acids for the Production of Linear Alpha

Olefins. Adv. Synth. Catal. 2014, 356, 130−136. (c) Chatterjee, A.;

Notes

The authors declare no competing ﬁnancial interest.

Hopen Eliasson, S. H.; Tornroos, K. W.; Jensen, V. R. Palladium

Precatalysts for Decarbonylative Dehydration of Fatty Acids to Linear

ACKNOWLEDGMENTS

Alpha Olefins. ACS Catal. 2016, 6, 7784−7789.

■

(12) (a) Cheng, W.-M.; Shang, R.; Fu, Y. Irradiation-Induced

We thank Jong Hee Song for the acquisition and analysis of

mass spectrometry data. All primary data ﬁles are available free

of charge at 10.13020/xpa3-w249.

Palladium-Catalyzed Decarboxylative Desaturation Enabled by a Dual

Ligand System. Nat. Commun. 2018, 9, 5215. (b) Tlahuext-Aca, A.;

Candish, L.; Garza-Sanchez, R. A.; Glorius, F. Decarboxylative

Olefination of Activated Aliphatic Acids Enabled by Dual Organo-

photoredox/Copper Catalysis. ACS Catal. 2018 , 8 , 1715 −1719.

Decarboxyolefination of Carboxylic Acids. Nat. Chem. 2018, 10,

1229−1233. (d) Nguyen, V. T.; Nguyen, V. D.; Haug, G. C.; Dang,

H. T.; Jin, S.; Li, Z.; Flores-Hansen, C.; Benavides, B. S.; Arman, H.

D.; Larionov, O. V. Alkene Synthesis by Photocatalytic Chemo-

enzymatically Compatible Dehydrodecarboxylation of Carboxylic

Acids and Biomass. ACS Catal. 2019, 9, 9485−9498.

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