TY - JOUR
T1 - Mechanistic Studies on the SCS-Pincer Palladium(II)-Catalyzed Tandem Stannylation/Electrophilic Allylic Substitution of Allyl Chlorides with Hexamethylditin and Benzaldehydes
AU - Pijnenburg, N.J.M.
AU - Cabon, Y.H.M.
AU - van Koten, G.
AU - Klein Gebbink, R.J.M.
PY - 2013
Y1 - 2013
N2 - This paper describes a mechanistic
study of the SCS-pincer PdII-catalyzed
auto-tandem reaction consisting
of the stannylation of cinnamyl chlo-
ACHTUNGTRENUNGride with hexamethylditin, followed by
an electrophilic allylic substitution of
the primary tandem-reaction product
with 4-nitrobenzaldehyde to yield homoallylic
alcohols as the secondary
tandem products. As it turned out, the
anticipated stannylation product, cinnamyl
trimethylstannane, is not a substrate
for the second part of the
tandem reaction. These studies have
provided insight in the catalytic behavior
of SCS-pincer PdII complexes in the
auto-tandem reaction and on the formation
and possible involvement of
Pd0 species during prolonged reaction
times. This has led to optimized reaction
conditions in which the overall
tandem reaction proceeds through
SCS-pincer PdII-mediated catalysis, that
is, true auto-tandem catalysis. Accordingly,
this study has provided the appropriate
reaction conditions that allow
the pincer catalysts to be recycled and
reused.
AB - This paper describes a mechanistic
study of the SCS-pincer PdII-catalyzed
auto-tandem reaction consisting
of the stannylation of cinnamyl chlo-
ACHTUNGTRENUNGride with hexamethylditin, followed by
an electrophilic allylic substitution of
the primary tandem-reaction product
with 4-nitrobenzaldehyde to yield homoallylic
alcohols as the secondary
tandem products. As it turned out, the
anticipated stannylation product, cinnamyl
trimethylstannane, is not a substrate
for the second part of the
tandem reaction. These studies have
provided insight in the catalytic behavior
of SCS-pincer PdII complexes in the
auto-tandem reaction and on the formation
and possible involvement of
Pd0 species during prolonged reaction
times. This has led to optimized reaction
conditions in which the overall
tandem reaction proceeds through
SCS-pincer PdII-mediated catalysis, that
is, true auto-tandem catalysis. Accordingly,
this study has provided the appropriate
reaction conditions that allow
the pincer catalysts to be recycled and
reused.
U2 - 10.1002/chem.201203049
DO - 10.1002/chem.201203049
M3 - Article
SN - 0947-6539
VL - 19
SP - 4858
EP - 4868
JO - Chemistry-A European Journal
JF - Chemistry-A European Journal
IS - 15
ER -