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New reactions of allenes, alkynes, ynamides, enynones and isothiocyanates
Ist Teil von
Journal of chemical sciences (Bangalore, India), 2018-07, Vol.130 (7), p.1-11, Article 99
Ort / Verlag
New Delhi: Springer India
Erscheinungsjahr
2018
Link zum Volltext
Quelle
Free E-Journal (出版社公開部分のみ)
Beschreibungen/Notizen
This perspective article is related to transformations (both catalytic and non-catalytic) involving allenes, alkynes/enynones/ynamides and isothiocyanates. Part of the work from the author’s group has been reviewed along with some new reactions of (i) allenylphosphonate/allenylphosphine oxide and (ii) a P(III) isothiocyanate. Thus, the allenylphosphine oxide
Ph
2
P(O)C(Ph)=C=CH
2
undergoes base (DBU) catalyzed addition to the
β
-ketophosphonate
(OCH
2
CMe
2
CH
2
O)P(O)CH
2
C(O)CH
3
at
90
∘
C
to afford the addition product
Ph
2
P(O)C(Ph)=C(Me)CH[C(O)Me][P(O)(OCH
2
CMe
2
CH
2
O)]
. In an analogous reaction, with DBU as the base at
140
∘
C
, isomeric vinylphosphine oxides (
Z
)-
Ph
2
P(O)C(Ph)=C(Me)CH
2
[C(O)Me]
and (
E
)-
Ph
2
P(O)C(Ph)=C(Me)CH
2
[C(O)Me]
were isolated. The
E
-isomer has been characterized by single crystal X-ray structure determination. In another set of studies, the reaction of P(III) isothiocyanate
(OCH
2
CMe
2
CH
2
O)P(NCS)
with
N
-(2-bromomethyl)sulfonamide afforded an unusual product with the formula
(OCH
2
CMe
2
CH
2
O)P(O)SCH
2
CH
2
NHS(O)
2
-
(
C
6
H
4
-4-
Me)
as shown by X-ray structure determination. This result is different from that obtained in the recently reported analogous reaction using phenyl isothiocyanate.
Graphical Abstract
Synopsis.
Base-catalyzed the addition of
β
-ketophosphonate or ethyl acetoacetate to allenylphosphine oxide affords vinylphosphine oxides; in the latter case, elimination of the ester group also takes place. It is also shown that reactivity of a P(III) isothiocyanate is different from that of organic isothiocyanates.