Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton containing group 14 and 15 elements with benzaldehyde

Article abstract of DOI:10.1080/10426507.2018.1514405

Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton containing Group 14 and 15 elements (PhSi, PhGe, PhSn, n-BuSn, P, As, Sb, and Bi) at another bridgehead position with benzaldehyde provided (Z)-olefins as a major product in the cases of period 3 elements (PhSi, P) and (E)-olefins as a major product in the cases of below period 4 elements (PhGe, PhSn, n-BuSn, As, Sb, and Bi). These results are attributed to stereochemical drift of the intermediates come from the heteroatom effect at another bridgehead position of the phosphaheteratriptycene skeleton.

Full text of DOI:10.1080/10426507.2018.1514405

Phosphorus, Sulfur, and Silicon and the Related Elements
ISSN: 1042-6507 (Print) 1563-5325 (Online) Journal homepage: http://www.tandfonline.com/loi/gpss20
Wittig reactions of non-stabilized phosphonium
ylides bearing a phosphaheteratriptycene skeleton
containing group 14 and 15 elements with
benzaldehyde
Yosuke Uchiyama, Suguru Kuniya, Ryo Watanabe & Takemaru Ohtsuki
To cite this article: Yosuke Uchiyama, Suguru Kuniya, Ryo Watanabe & Takemaru Ohtsuki
(2018): Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene
skeleton containing group 14 and 15 elements with benzaldehyde, Phosphorus, Sulfur, and Silicon
and the Related Elements, DOI: 10.1080/10426507.2018.1514405
To link to this article: https://doi.org/10.1080/10426507.2018.1514405
Published online: 05 Oct 2018.
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PHOSPHORUS, SULFUR, AND SILICON AND THE RELATED ELEMENTS
https://doi.org/10.1080/10426507.2018.1514405
Wittig reactions of non-stabilized phosphonium ylides bearing a
phosphaheteratriptycene skeleton containing group 14 and 15
elements with benzaldehyde
Yosuke Uchiyama, Suguru Kuniya, Ryo Watanabe, and Takemaru Ohtsuki
Department of Chemistry, School of Science, Kitasato University, Sagamihara, Japan
ABSTRACT
ARTICLE HISTORY
Wittig reactions of non-stabilized phosphonium ylides bearing a phosphaheteratriptycene skeleton
containing Group 14 and 15 elements (PhSi, PhGe, PhSn, n-BuSn, P, As, Sb, and Bi) at another
bridgehead position with benzaldehyde provided (Z)-olefins as a major product in the cases of
period 3 elements (PhSi, P) and (E)-olefins as a major product in the cases of below period 4 ele-
ments (PhGe, PhSn, n-BuSn, As, Sb, and Bi). These results are attributed to stereochemical drift of
the intermediates come from the heteroatom effect at another bridgehead position of the phos-
phaheteratriptycene skeleton.
Received 19 July 2018
Accepted 16 August 2018
KEYWORDS
Wittig reaction; non-
stabilized phosphonium
ylide; phosphaheteratripty-
cene; 1,2-oxaphosphetane;
heteroatom effect
GRAPHICAL ABSTRACT
Results and discussion
generated by the deprotonation of the corresponding ethyl-
phosphonium iodides with TMS NNa, with PhCHO were
2
Alkyl groups on the phosphorus atom of non-stabilized
phosphonium ylides affect stereochemical drift, leading to
ꢀ
conducted at –90 C in THF and the reaction mixtures were
ꢀ
allowed to warm to 25 C for over 3 hours (Scheme 1).
(E)-selective olefin formation as reported in the Wittig reac-
Wittig reactions provided (Z)-olefins as major product in
the cases of period 3 elements (PhSi, P in entries 1 and 5 of
Table 1) and (E)-olefins as a major product in the cases of
below period 4 elements (PhGe, PhSn, n-BuSn, As, Sb, and
Bi in entries 2–4 and 6–8 of Table 1). The selectivity of the
olefin formation under the reaction condition was attributed
to the heteroatom effect at another bridgehead position of a
phosphaheteratriptycene skeleton on stereochemical drift by
the isomerization from cis-1,2-oxaphosphetanes 2a to trans-
forms 2b in Scheme 1.
tion of stabilized phosphonium ylide with carbonyl com-
[1,2]
pounds.
We have previously revealed the origin of
stereochemical drift of the intermediates in (E)-selective
Wittig reactions of a non-stabilized phosphonium ylide bear-
ing a phosphastibatriptycene skeleton, which contains Sb at
another bridgehead position with benzaldehydes based on the
observation of the isomerization from cis-1,2-oxaphosphetanes
31
1
[3–5]
to trans-forms by VT- P{ H} NMR spectroscopy.
Herein,
we wish to report on Wittig reactions of non-stabilized phos-
phonium ylides 1 bearing a phosphaheteratriptycene skeleton
containing Group 14 and 15 elements (Si, Ge, Sn, P, As, Bi)
at another bridgehead position with benzaldehyde (PhCHO)
The isomerization of 1,2-oxaphosphetanes bearing a phos-
phaheteratriptycene skeleton containing Group 15 elements
ꢀ
ꢀ
ꢀ
[3,4]
in order to clarify the effect of elements involved in the tri- was observed at 0 C for P, –20 C for As, –40 C for Sb,
ꢀ
31
1
dentate ligands on the phosphorus atom of the ylides.
and –60 C for Bi by VT- P{ H} NMR spectroscopy, the
Wittig reactions of non-stabilized phosphonium ylides 1 temperature of which became lower as a raw number
bearing a phosphaheteratriptycene skeleton, which were increases (Table 1, entries 1–4). It was comparable with the
CONTACT Yosuke Uchiyama
yosuke@kitasato-u.ac.jp
Department of Chemistry, School of Science, Kitasato University, 1-15-1 Kitasato, Minami-ku,
Sagamihara 252-0373, Japan.
ß 2018 Taylor & Francis Group, LLC

2
Y. UCHIYAMA ET AL.
Scheme 1. Wittig reactions of non-stabilized phosphonium ylides 1 bearing a phosphaheteratriptycene skeleton (M ¼ P, As, Sb, PhSi, PhGe, PhSn, n-BuSn)
with PhCHO.
Table 1. Yields and (E)/(Z) ratios of olefins produced in the Wittig reaction.
[6]
ꢀ
a
Entry
M
Electronegativity
Isomerization temperature ( C)
Yield (%)
(E)/(Z) ratio
1
2
3
4
5
6
7
8
a
P
2.19
2.18
2.05
2.02
1.90
2.01
1.96
1.96
0
15
32
87
43
39
72
34
45
49/51
65/35
87/13
74/26
38/62
83/17
79/21
74/26
As
–20
–40
–60
–20
–50
–50
–60
[3,4]
Sb
Bi
PhSi
PhGe
PhSn
n-BuSn
31
1
Observed by VT- P{ H} NMR spectroscopy.
[6]
tendency of electronegativity , affecting M–C polarization of and Technology of Japan and Kitasato University Research Grant for
Young Researchers.
a phosphaheteratriptycene skeleton. On the other hand,
Group 14 elements substituted by the phenyl group at
another bridgehead position did not show the similar electric
References
[6]
effect based on the electronegativity , judging from the iso-
ꢀ
ꢀ
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ꢀ
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ꢀ
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Acknowledgment
The authors thank Emeritus Prof. Takayuki Kawashima for useful advices.
[4] Uchiyama, Y.; Ohtsuki, T.; Murakami, R.; Shibata, M.;
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Disclosure statement
No potential conflict of interest was reported by the authors.
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Funding
This study was partially supported by
Encouragement of Young Scientists (B) to Y. U. (No.16750041 and
No.18750037) from the Ministry of Education, Culture, Sports, Science,
a
Grant-in-Aid for
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