Shelf-Stable (E)- A nd (Z)-Vinyl-λ3-chlorane: A Stereospecific Hyper-vinylating Agent

Article abstract of DOI:10.1021/acs.orglett.0c00924

We report the first stereoselective synthesis of stable (E)- A nd (Z)-β-chlorovinyl-λ³-chlorane via direct mesitylation of 1,2-dichloroethylene with mesityldiazonium tetrakis(pentafluorophenyl)borate under mild reaction conditions. The structure of the (E)-vinyl-λ³-chlorane was established by single-crystal X-ray analysis. Because of the enormously high leaving group ability of the aryl-λ³-chloranyl group, vinyl-λ³-chloranes undergo not only S_NVσ-type reaction with extremely weak nucleophiles such as perfluoroalkanesulfonate, iodobenzene, and aromatic hydrocarbons but also coupling with phenylcopper(I) species.

Full text of DOI:10.1021/acs.orglett.0c00924

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Letter
Shelf-Stable (E)- and (Z)‑Vinyl‑λ3‑chlorane: A Stereospecific Hyper-
vinylating Agent
Yuichiro Watanabe, Taisei Takagi, Kazunori Miyamoto,* Junichiro Kanazawa,
and Masanobu Uchiyama*
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ABSTRACT: We report the first stereoselective synthesis of
stable (E)- and (Z)-β-chlorovinyl-λ3-chlorane via direct mesityla-
tion of 1,2-dichloroethylene with mesityldiazonium tetrakis-
(pentafluorophenyl)borate under mild reaction conditions. The
structure of the (E)-vinyl-λ3-chlorane was established by single-
crystal X-ray analysis. Because of the enormously high leaving
group ability of the aryl-λ3-chloranyl group, vinyl-λ3-chloranes
undergo not only SNVσ-type reaction with extremely weak
nucleophiles such as perfluoroalkanesulfonate, iodobenzene, and
aromatic hydrocarbons but also coupling with phenylcopper(I)
species.
he concerted bimolecular nucleophilic substitution (SN)
of ethylene chloride with Me/EtF−SbF5.8 However, unfortu-
nately the λ3-chloranes 3 were too unstable to be isolated and
were characterized only at −90 °C. Other attempted
electrophilic attacks on vinyl chloride (e.g., transylidations
with N-triflylimino-λ3-bromane/bromonium ylide,9,10 phenyl-
ation with phenyldiazonium tetrafluoroborate, and oxidation
with chlorine trifluoride) were all unsuccessful and resulted in
degradation/polymerization of the starting materials. Gratify-
ingly, the use of mesityldiazonium tetrakis(pentafluorophenyl)-
3
Treaction at sp carbon is one of the best-understood
mechanisms in organic chemistry.1 In contrast, nucleophilic
substitution at sp2 carbon with inversion of stereochemistry
(SNVσ) has been shown to proceed only in specific cases.2,3
For example, vinyl chloride/bromide-containing nucleophilic
functionalities tethered with a suitable alkyl chain undergo
intramolecular SNVσ reaction to form a variety of carbo/
heterocycles (Figure 1a).3a−d Metal vinylcarbenoid also serves
as a good substrate, partly because of the metal-assisted
elimination of leaving groups (Figure 1b).3e−m However, these
substrates rarely undergo intermolecular transformations. In
marked contrast, hypervalent vinyl-λ3-iodane 1 undergoes
intermolecular SNVσ reaction with a variety of Group 15−17
heteroatom nucleophiles under mild reaction conditions
(Figure 1c).4 This intermolecular SNVσ reaction was first
demonstrated with the λ3-iodanyl group (−I(Ph)FBF3), a so-
called hyper-leaving group that is ca. 106 times more effective
than triflate (−OSO2CF3),5 enabling it to drive this extremely
difficult type of transformation. It occurred to us that the
introduction of an even more potent leaving group, the λ3-
chloranyl group (−Cl(Ar)X),6,7 might greatly expand the range
of applicable nucleophiles. We report herein the first
stereoselective synthesis of shelf-stable (E)- and (Z)-β-
chlorovinyl-λ3-chlorane 2 that functions as a stereospecific
electrophilic vinylating agent not only toward common
heteroatom nucleophiles but also toward simple aromatic
hydrocarbons under mild conditions (Figure 1d).
−
borate [B(C6F5)4 ] (4) proved to be a game-changer.
Recently, we reported that the thermal decomposition of 4
in chloroarenes selectively afforded diaryl-λ3-chloranes.7 The
direct mesitylation protocol tolerates π-electrons of vinyl
chloride, and undesired polymerized products are not formed.
Thus, exposure of 4 to trans-1,2-dichloroethylene (5) (30
equiv) at room temperature under air resulted in a slow but
chlorine-selective mesitylation and afforded the corresponding
(E)-vinyl-λ3-chlorane 2 almost quantitatively (Scheme 1). Use
of pentafluorobenzene accelerated the reaction without
decreasing the yield.11 This transformation could be operated
on a gram scale with comparable yield: (E)-2 was obtained in
86% yield (0.48 g). The Z-isomer (Z)-2 was also obtained in
Received: March 12, 2020
There has been only one report of a synthesis of
vinyl(alkyl)-λ3-chlorane 3, which involved a direct methylation
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Figure 2. 1H NMR and 13C NMR chemical shifts of vinylic protons/
carbons: δ values in ppm in CDCl3.
ability of the λ3-chloranyl group (Hammett σI for −Cl(Ph)BF4:
1.72).12 This consideration is in good agreement with the
smaller coupling constants between vicinal vinylic protons
(Jtrans 11.6 Hz; Jcis 4.1 Hz) compared to dihaloethylene such as
2-chloro-1-iodoethene (Jtrans 13.5 Hz; Jcis 5.8 Hz)13 and (E)/
(Z)-vinyl-λ3-iodanes and λ3-bromanes.14,15 On the other hand,
a negligibly small chemical shift change of the α carbon in 2
was observed, presumably due, at least in part, to the negligible
spin−orbit effect (heavy atom effect) of the chlorine atom.16
Recrystallization from CH2Cl2−hexane at −20 °C afforded
single crystals of (E)-isomer 2 that were suitable for X-ray
crystallography. Figure 3 shows the structure of the (E)-2-
Figure 1. Vinylic SN2 (SNVσ) reaction of (a) vinyl halide
(intramolecular), (b) metal carbenoid (intra/intermolecular), (c)
vinyl-λ3-iodane (intermolecular), and (d) vinyl-λ3-chlorane (inter-
molecular, this work).
Scheme 1. Stereoselective Synthesis of (E)- and (Z)-β-
Chlorovinyl-λ3-chloranes 2
Figure 3. ORTEP drawing of (E)-2 with thermal ellipsoids at 50%
probability. The BArf4− anion containing F21) was omitted for clarity.
For symmetry operation: 1) X, −Y + 1, Z + 1.
chlorovinyl(mesityl)chloronium unit stabilized by the fluorine
atoms of B(C6F5)4− anions. While the large C1−Cl1−C2 bond
angle (105.25°) suggests onium-like character of the Cl(III)
center,7,17 the close contacts Cl1···F1 (3.033 Å) and Cl1···F21)
(3.045 Å) probably constitute a part of a distorted three-center
four-electron (3c-4e) hypervalent bonding, due to the large
bond angles of C1−Cl1···F1 and C2−Cl1···F21) (150.4° and
143.1°). In the vinyl unit, the vinylic C2−C3 bond length is
comparable to the reported value of common Csp2Csp2
bonds (1.31−1.32 Å).18 On the other hand, the Cl1−C1
bond length (1.788 Å) is considerably longer than that of the
Cl2−C3 bond (1.696 Å) or the bonds in 1,2-dichloroethylene
5 (1.71 Å), but it is close to that of the Cl(III)−Csp2 bond of
diaryl-λ3-chloranes.7 The smaller angle of Cl1−C2−C3
(117.0°) compared to the common sp2 angle of 120° probably
reflects the carbocationic character of the C2 center.19 2-
Chlorovinyl-λ3-chlorane (E)-2 thus synthesized serves as a
tremendously active electrophile toward a variety of
nucleophiles (Schemes 2 and S2). The SNVσ reaction of
vinyl-λ3-iodane 1a with thiobenzamide 6 yielding (Z)-vinyl-
thioimidonium salt 7 takes place, but the reaction is very
sluggish at room temperature and requires a prolonged
high yield under similar conditions without formation of the E-
isomer (Scheme S1).
The (E)/(Z)-vinyl-λ3-chloranes 2 are colorless crystalline
compounds, which show surprising thermal and moisture
stability: no decomposition was detected under air without
shielding from light for at least 1 year at room temperature for
(E)-2 and for 1 week at room temperature (months in a
refrigerator at 4 °C) in the case of (Z)-2. In solution, however,
both compounds are rather unstable and gradually decompose
at ambient temperature. For example, in CDCl3 at 23 °C, the
half-life times (t1/2) of 40 h for (E)-2 and 22 h for (Z)-2 were
observed. The compounds are much less stable in more polar
solvents, especially the (Z)-isomer: (E)-2 is about 5 times
more stable than (Z)-2 in CD3CN (t1/2 of 8 h for (E)-2; 1.6 h
for (Z)-2 at 23 °C) and ≥24 times more stable in acetic acid-d4
1
(t1/2 of 4 h for (E)-2; <10 min for (Z)-2 at 23 °C). In the H
NMR and 13C NMR spectra of 2 (Figure 2), the vinylic α and
β protons and vinylic β carbon of (E)/(Z)-2 are significantly
deshielded compared to those of the parent 1,2-dichloro-
ethylene 5, probably reflecting the potent electron-withdrawing
B
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afford inverted (Z)-β-chlorovinyl-λ3-iodane 18 stereoselec-
tively. This is the first example of the stereoinvertive vinylation
of iodobenzene. Although the precise reason for the low vinylic
SN2σ selectivity is unclear, vinylic SN2σ/SNAr selectivity is
known to be affected by stereoelectronic factors, solvent
polarity, temperature, etc.2b,4,21
Scheme 2. Reaction of (E)-β-Chlorovinyl-λ3-chlorane (E)-2
During the vinylation of haloarenes, we unexpectedly found
that simple aromatic hydrocarbons also served as efficient
nucleophiles. Thus, treatment of (E)-2 with mesitylene (20) at
30 °C stereoselectively afforded 1-[(Z)-2-chlorovinyl]- 2,4,6-
trimethylbenzene (21) in high yield (Scheme 2). (Z)-2 also
serves as stereospecific electrophile. These reactions were,
however, sensitive to the π-electron density. For example,
vinylation of durene (22) smoothly proceeded in 86% yield,
while benzene with 2 did not give any vinylation product at all,
but instead only mesitylation reaction took place (Table S2 in
the Supporting Information). Given the features of the unusual
vinylation of arene, i.e., (1) it follows second-order kinetics,
(2) (Z)-2 reacts faster than (E)-2,14 and (3) there is a small
and positive activation entropy ΔS‡ (1.4 cal mol−1 K−1), the
reaction probably proceeds via an SNVσ-type mechanism
(Scheme S3, Figures S1 and S2, in the Supporting
Information).
To gain mechanistic insights of this untraversed reaction, we
performed DFT calculations using model compounds: (E)-β-
chlorovinyl(mesityl)chloronium ion and mesitylene (Figure 4).
Figure 4. DFT calculation (M06-2X/6-31+G**).
reaction time.4d In contrast, (E)-2 reacts instantaneously with
6 at room temperature to afford the completely inverted (Z)-
vinylthioimidonium salt 8 in high yield, indicating the
enhanced nucleofugality of the λ3-chloranyl group. Similarly,
sterically hindered diphenyl sulfide (9) smoothly underwent
SNVσ reaction with both (E)- and (Z)-2 in high yields. The
hyper-vinylating agent (E)-2 undergoes SNVσ reaction with the
much more weakly nucleophilic p-toluenesulfonate ion 12 at
room temperature. This, to our knowledge, is the only example
of the synthesis of (Z)-β-chlorovinyl tosylate 13 with complete
stereoselectivity. Under these reaction conditions, possible
undesired side reactions such as elimination of vinylic α/β-
proton, ligand coupling, and mesitylation of nucleophile were
not observed at all. In marked contrast, under these conditions,
(Z)-2 did not produce the corresponding (E)-vinyl tosylate,
probably because of the stereoelectronically favored anti-β-
elimination process. The superacid counterion n-C7F15SO3− 14
(the conjugate acid’s H0 is lower than −12)20 also functions as
a potent nucleophile toward (E)-2, though this reaction is
accompanied by formation of the O-mesitylated product 16.
The direct vinylation of iodobenzene (17) with 2 proceeded to
The vinylation step is computed to be a concerted process of
C−Cl(III) bond cleavage and CAr−Cvinyl bond formation with
an activation barrier of 19.6 kcal mol−1 leading to the σ-
complex (IM2). In the TS, the vinylic α-carbon takes a nearly
sp-hybridized configuration, which is comparable to the
reported TS of SNVσ reactions.22,2a The transient IM2 would
lead to barrierless deprotonation (rearomatization) to give the
stable product (Z)-β-chlorovinylmesitylene (Z)-21.
Organometallics are widely utilized in C−C bond-forming
reactions, but they generally do not work well with hypervalent
vinyl-λ3-iodanes due to their high basicity, which favors
deprotonation reaction over bond-forming reaction.15,23,24
Preliminary work has shown that organocopper reagents
offer unique reactivity and chemo-/stereoselectivity with
vinyl-λ3-chloranes 2 (Scheme 3).25 Exposure of (E)-2 to
phenylcopper(I) 24 in dichloromethane at −78 °C to room
temperature resulted in the formation of the coupling product
(E)-β-chlorostyrene (E)-(25) in 88% yield with full retention
of configuration, while the reaction of (Z)-2 proceeded
smoothly to give exclusively (Z)-25 in 89% yield. Further
C
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Scheme 3. Stereoselective Phenylation of Vinyl-λ3-chlorane
Notes
2 with Phenylcopper(I) 24
The authors declare no competing financial interest.
ACKNOWLEDGMENTS
■
This work was supported by grants from JSPS KAKENHI (B),
(17H03017) (to K.M.), JSPS KAKENHI (S) (17H06173) (to
M.U.), JSPS KAKENHI (19K23621) (to J.K.), JST CREST
(JPMJCR19R2) (to M.U.), Nagase Science & Technology
Development Foundation (to M.U.), and Sumitomo Founda-
tion (to M.U.).
work to examine the scope of the reaction and to elucidate the
reaction pathway with the help of theoretical and spectroscopic
studies is in progress.
In conclusion, we present the first synthesis and character-
ization of (E)- and (Z)-vinyl-λ3-chlorane 2, which serves as a
potent SNVσ type vinylating agent. These reagents enable
direct, metal-free CAr−Cvinyl bond formation via SNVσ reaction
of 2 with simple aromatic hydrocarbons. Further work on
hypervalent λ3-chlorine reagents and their applications is under
way.
REFERENCES
■
(1) Carey, F. A.; Sundberg, R. J. Advanced organic chemistry; Kluwer
Academic: New York, 2000.
(2) Reviews. (a) Chiba, S.; Ando, K.; Narasaka, K. Concerted
nucleophilic substitution reactions at vinylic carbons. Synlett 2009,
2009, 2549. (b) Okuyama, T. Vinylic SN2 reaction. Yuki Gosei Kagaku
Kyokaishi 2006, 64, 348. (c) Satoh, T. Recent advances in the
chemistry of magnesium carbenoids. Chem. Soc. Rev. 2007, 36, 1561.
(3) (a) Lei, M.-Y.; Xiao, Y.-J.; Liu, W.-M.; Fukamizu, K.; Chiba, S.;
Ando, K.; Narasaka, K. Nucleophilic substitution reaction at an sp2
carbon of vinyl halides with an intramolecular thiol moiety: synthesis
of thio-heterocycles. Tetrahedron 2009, 65, 6888. (b) Miyauchi, H.;
Chiba, S.; Fukamizu, K.; Ando, K.; Narasaka, K. Synthesis of hetero-
and carbocycles by nucleophilic substitution at sp2 carbon.
Tetrahedron 2007, 63, 5940. (c) Ando, K.; Kitamura, M.; Miura, K.;
Narasaka, K. Theoretical and experimental study on the in-plane SN2-
type substitution reaction of haloalkenes with inversion of
configuration at the sp2 carbon. Org. Lett. 2004, 6, 2461. (d) Shiers,
J. J.; Shipman, M.; Hayes, J. F.; Slawin, A. M. Z. Rare example of
nucleophilic substitution at vinylic carbon with inversion: mechanism
of methyleneaziridine formation by sodium amide induced ring
closure revisited. J. Am. Chem. Soc. 2004, 126, 6868. (e) Duraisamy,
M.; Walborsky, H. M. Chiral vinyllithium reagents. Carbenoid
reactions. J. Am. Chem. Soc. 1984, 106, 5035. (f) Yanagisawa, H.;
Miura, K.; Kitamura, M.; Narasaka, K.; Ando, K. Intramolecular
substitution reaction of lithium alkylidene carbenoids. Regioselective
synthesis of indenes. Bull. Chem. Soc. Jpn. 2003, 76, 2009. (g) Brown,
H. C.; Basavaiah, D.; Kulkarni, S. U.; Lee, H. D.; Negishi, E.; Katz, J.-
J. Vinylic organoboranes. 6. A general synthesis of (E)-disubstituted-
alkenes or ketones via the (E)-(1-substituted-1-alkenyl)boronic esters.
J. Org. Chem. 1986, 51, 5270. (h) Harada, T.; Katsuhira, T.; Hara, D.;
Kotani, Y.; Maejima, K.; Kaji, R.; Oku, A. Reactions of 1,1-
dihaloalkenes with triorganozincates: a novel method for the
preparation of alkenylzinc species associated with carbon-carbon
bond formation. J. Org. Chem. 1993, 58, 4897. (i) Miller, J. A. An
unprecedented intramolecular migration of carbon groups from
aluminum to an adjacent vinylic center and its application to the
synthesis of stereodefined olefins. J. Org. Chem. 1989, 54, 998.
(j) Baati, R.; Barma, D. K.; Falck, J. R.; Mioskowski, C. Chromium
vinylidene carbenoids: generation, characterization, and reactivity.
First evidence for an internal proton return phenomenon with
vinylidene carbenoids. J. Am. Chem. Soc. 2001, 123, 9196. (k) Negishi,
E.; Akiyoshi, K.; O’Connor, B.; Takagi, K.; Wu, G. Migratory
insertion reactions of organometallics. 3. Carbon-carbon bond
forming reactions of organotransition metals with α- or γ-
haloorganolithium reagents. J. Am. Chem. Soc. 1989, 111, 3089.
(l) Kasatkin, A.; Whitby, R. J. Zirconium mediated synthesis.
Convergent access to terminal trienes, dienes, and dienynes.
Tetrahedron Lett. 1997, 38, 4857. (m) Kasatkin, A.; Whitby, R. J.
Insertion of 1-chloro-1-lithioalkenes into organozirconocenes. A
versatile synthesis of stereodefined unsaturated systems. J. Am.
Chem. Soc. 1999, 121, 7039. (n) Satoh, T.; Mori, N.; Obuchi, K.
Alkenylation of thiophenes at the 2-position with magnesium
alkylidene carbenoids. Tetrahedron Lett. 2007, 48, 6453. (o) Yama-
guchi, T.; Yamamoto, Y.; Fujiwara, Y.; Tanimoto, Y. Evidence for a
ASSOCIATED CONTENT
* Supporting Information
■
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The Supporting Information is available free of charge at
https://pubs.acs.org/doi/10.1021/acs.orglett.0c00924.
Experimental procedures, characterization data, theoreti-
cal data, and NMR spectra (PDF)
Accession Codes
CCDC 1983270 contains the supplementary crystallographic
data for this paper. These data can be obtained free of charge
via www.ccdc.cam.ac.uk/data_request/cif, or by emailing
data_request@ccdc.cam.ac.uk, or by contacting The Cam-
bridge Crystallographic Data Centre, 12 Union Road,
Cambridge CB2 1EZ, UK; fax: +44 1223 336033.
AUTHOR INFORMATION
Corresponding Authors
■
Kazunori Miyamoto − Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033,
Japan; orcid.org/0000-0003-1423-6287; Email: kmiya@
mol.f.u-tokyo.ac.jp
Masanobu Uchiyama − Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033,
Japan; Research Initiative for Supra-Materials (RISM), Shinshu
University, Ueda 386-8567, Japan; Cluster of Pioneering
Research (CPR), RIKEN, Wako-shi, Saitama 351-0198,
Japan; orcid.org/0000-0001-6385-5944;
Email: uchiyama@mol.f.u-tokyo.ac.jp
Authors
Yuichiro Watanabe − Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033,
Japan
Taisei Takagi − Graduate School of Pharmaceutical Sciences,
The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan
Junichiro Kanazawa − Graduate School of Pharmaceutical
Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033,
Japan; orcid.org/0000-0001-6227-0864
Complete contact information is available at:
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transition state model compound of in-plane vinylic SN2 reaction. Org.
Lett. 2005, 7, 2739.
(17) Stoyanov, E. S.; Stoyanova, I. V.; Tham, F. S.; Reed, C. A.
Dialkyl chloronium ions. J. Am. Chem. Soc. 2010, 132, 4062.
(18) Allen, F. H.; Kennard, O.; Watson, D. G.; Brammer, L.; Orpen,
A. G.; Taylor, R. Tables of bond lengths determined by X-ray and
neutron diffraction. Part 1. Bond lengths in organic compounds. J.
Chem. Soc., Perkin Trans. 2 1987, 2, S1.
(19) Wiberg, K. B.; Rablen, P. R. Substituent effects. 5. Vinyl and
ethynyl derivatives. An examination of the interaction of amino and
hydroxy groups with carbon-carbon double and triple bonds. J. Am.
Chem. Soc. 1993, 115, 9234.
(20) Yu, J.; Li, Z. Synthesis of liquid antioxidant DTBNP catalyzed
by composite super acid. Open Catal. J. 2010, 2, 169.
(21) Okuyama, T.; Takino, T.; Sato, K.; Oshima, K.; Imamura, S.;
Yamataka, H.; Asano, T.; Ochiai, M. Vinylic SN2 reaction of 1-
decenyliodonium salt with halide ions. Bull. Chem. Soc. Jpn. 1998, 71,
243.
(22) (a) Okuyama, T.; Yamataka, H. A theoretical study on the
reactivity of vinyl iodonium ions. Can. J. Chem. 1999, 77, 577.
(b) Bach, R. D.; Baboul, A. G.; Schlegel, H. B. Inversion versus
retention of configuration for nucleophilic substitution at vinylic
carbon. J. Am. Chem. Soc. 2001, 123, 5787. (c) Glukhovtsev, M. N.;
Pross, A.; Radom, L. Is SN2 substitution with inversion of
configuration at vinylic carbon feasible? J. Am. Chem. Soc. 1994,
116, 5961.
(23) (a) Fujita, M.; Ihara, K.; Kim, W. H.; Okuyama, T. Generation
of cycloheptyne during the solvolysis of cyclohexylidenemethyliodo-
nium salt in the presence of base. Bull. Chem. Soc. Jpn. 2003, 76, 1849.
(b) Okuyama, T.; Fujita, M. Generation of cycloalkynes by hydro-
iodonio-elimination of vinyl iodonium salts. Acc. Chem. Res. 2005, 38,
679.
(4) (a) Ochiai, M.; Oshima, K.; Masaki, Y. Inversion of
configuration in nucleophilic vinylic substitutions of (E)-β-alkylviny-
liodonium tetrafluoroborates with halides. J. Am. Chem. Soc. 1991,
113, 7059. (b) Okuyama, T.; Takino, T.; Sato, K.; Ochiai, M. In-plane
vinylic SN2 substitution and intramolecular β elimination of β-
alkylvinyl(chloro)-λ3-iodanes. J. Am. Chem. Soc. 1998, 120, 2275.
(c) Ochiai, M.; Nishi, Y.; Hirobe, M. Nucleophilic vinylic
substitutions of (Z)-(2-aroyloxyvinyl)phenyl-λ3-iodanes with tetrabu-
tylammonium halides: vinylic SN2 reactions and ligand coupling on
iodine(III). Tetrahedron Lett. 2005, 46, 1863. (d) Ochiai, M.;
Yamamoto, S. Vinyl-λ3-iodanes act as efficient sulfur atom acceptors:
vinylic SN2-based strategy for conversion of tertiary thioamides to
amides. Chem. Commun. 2002, 2802.
(5) Okuyama, T.; Takino, T.; Sueda, T.; Ochiai, M. Solvolysis of
cyclohexenyliodonium salt, a new precursor for the vinyl cation:
remarkable nucleofugality of the phenyliodonio group and evidence
for internal return from an intimate ion−molecule pair. J. Am. Chem.
Soc. 1995, 117, 3360.
(6) Miyamoto, K.; Iwasaki, S.; Doi, R.; Ota, T.; Kawano, Y.;
Yamashita, J.; Sakai, Y.; Tada, N.; Ochiai, M.; Hayashi, S.; Nakanishi,
W.; Uchiyama, M. Mechanistic studies on the generation and
properties of superelectrophilic singlet carbenes from bis-
(perfluoroalkanesulfonyl)bromonium ylides. J. Org. Chem. 2016, 81,
3188.
(7) Nakajima, M.; Miyamoto, K.; Hirano, K.; Uchiyama, M. Diaryl-
λ3-chloranes: versatile synthesis and unique reactivity as aryl cation
equivalent. J. Am. Chem. Soc. 2019, 141, 6499.
(8) Olah, G. A.; Prakash, G. K. S.; Bruce, M. R. Onium ions. 30.
Methyl- and ethylvinylhalonium ions. J. Org. Chem. 1985, 50, 2405.
(9) Ochiai, M.; Tada, N.; Okada, T.; Sota, A.; Miyamoto, K.
Thermal and catalytic transylidations between halonium ylides and
synthesis and reaction of stable aliphatic chloronium ylides. J. Am.
Chem. Soc. 2008, 130, 2118.
(10) (a) Ochiai, M.; Nakano, A.; Yoshimura, A.; Miyamoto, K.;
Hayashi, S.; Nakanishi, W. Imido transfer of sulfonylimino-λ3-
bromane makes possible the synthesis of sulfonylimino-λ3-iodanes.
Chem. Commun. 2009, 959, 959. (b) Ochiai, M.; Miyamoto, K.;
Hayashi, S.; Nakanishi, W. Hypervalent N-sulfonylimino-λ3-bromane:
active nitrenoid species at ambient temperature under metal-free
conditions. Chem. Commun. 2010, 46, 511.
(11) After the screening of cosolvent, addition of pentafluoroben-
zene was found to be optimal: with this solvent, the amount of 5
could be reduced to 6 equiv (Table S1 in the Supporting
Information).
(12) Grushin, V. V. Carboranylhalonium ions: from striking
reactivity to a unified mechanistic analysis of polar reactions of
diarylhalonium compounds. Acc. Chem. Res. 1992, 25, 529.
(13) Van Bergen, T. J.; Hedstrand, D. M.; Kruizinga, W. H.; Kellogg,
R. M. Chemistry of dihydropyridines. 9. Hydride transfer from 1,4-
dihydropyridines to sp3-hybridized carbon in sulfonium salts and
activated halides. Studies with NAD(P)H models. J. Org. Chem. 1979,
44, 4953.
(24) For limited examples of C−C bond formation reaction of (E)-
vinyl-λ3-iodane in the presence/absence of metal catalyst, see:
(a) Zhang, L.; Oestreich, M. Copper-catalyzed cross-coupling of
vinyliodonium salts and zinc-based silicon nucleophiles. Org. Lett.
2018, 20, 8061. (b) Liu, C.; Wang, Q. Alkenylation of C(sp3)−H
bonds by zincation/copper-catalyzed cross-coupling with iodonium
salts. Angew. Chem., Int. Ed. 2018, 57, 4727. (c) Suero, M. G.; Bayle,
E. D.; Collins, B. S. L.; Gaunt, M. J. Copper-catalyzed electrophilic
carbofunctionalization of alkynes to highly functionalized tetrasub-
stituted alkenes. J. Am. Chem. Soc. 2013, 135, 5332. (d) Skucas, E.;
MacMillan, D. W. C. Enantioselective α-vinylation of aldehydes via
the synergistic combination of copper and amine catalysis. J. Am.
Chem. Soc. 2012, 134, 9090. (e) Stridfeldt, E.; Seemann, A.; Bouma,
M. J.; Dey, C.; Ertan, A.; Olofsson, B. Synthesis, characterization and
unusual reactivity of vinylbenziodoxolones−Novel hypervalent iodine
reagents. Chem. - Eur. J. 2016, 22, 16066. (f) Rajkiewicz, A. A.; Kalek,
M. N-Heterocyclic carbene-catalyzed olefination of aldehydes with
vinyliodonium salts to generate α,β-unsaturated ketones. Org. Lett.
2018, 20, 1906. (g) Zhdankin, V. V. Hypervalent iodine chemistry:
preparation, structure and synthetic application of polyvalent iodine
compounds; John Wiley & Sons Ltd.: New York, 2014.
(25) Use of phenyllithium or phenylmagnesium bromide, instead of
phenylcopper, did not give satisfactory results partly because of the
undesired α/β-elimination of vinyl-λ3-chlorane (E)-2.
(14) Miyamoto, K.; Okubo, T.; Hirobe, M.; Kunishima, M.; Ochiai,
M. Effects of stereochemistry and β-substituents on the rates of vinylic
SN2 reaction of hypervalent vinyl(phenyl)-λ3-iodanes with tetrabuty-
lammonium halides. Tetrahedron 2010, 66, 5819.
(15) Ochiai, M.; Okubo, T.; Miyamoto, K. Weakly nucleophilic
conjugate bases of superacids as powerful nucleophiles in vinylic
bimolecular nucleophilic substitutions of simple β-alkylvinyl(aryl)-λ3-
bromanes. J. Am. Chem. Soc. 2011, 133, 3342.
(16) (a) Kaupp, M.; Malkina, O. L.; Malkin, V. G. The role of π-type
nonbonding orbitals for spin-orbit induced NMR chemical shifts:
DFT study of 13C and 19F shifts in the series CF3IFn (n = 0, 2, 4, 6). J.
Comput. Chem. 1999, 20, 1304. (b) Ochiai, M.; Nishi, Y.; Goto, S.;
Shiro, M.; Frohn, H. J. Synthesis, structure, and reaction of 1-
alkynyl(aryl)-λ3-bromanes. J. Am. Chem. Soc. 2003, 125, 15304.
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