Limits...
Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals

View Article: PubMed Central - HTML - PubMed

ABSTRACT

A cooperative catalytic strategy of chiral iminium catalysis by regioselective activation of the C=C bond in enals and a transition metal promoting to open the 2-vinylcyclopropanes for highly regio- and enantioselective [3 + 2] cycloaddition reaction of 2-vinylcyclopropanes with α,β-unsaturated aldehydes has been developed.

No MeSH data available.


The proposed transition states.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4979765&req=5

C3: The proposed transition states.

Mentions: We proposed two possible transition states (TS) 8a’ and 8a” to rationalize the observed configurations (Scheme 3). The trans-C=C double bond in iminium ion 4 dictates the R group at pseudo axial position in the cyclic 5-membered ring TS 8a’ and 8a”. This orientation avoids the A[1,3] strain induced by the catalyst-derived enamine. The Pd(II)-π3 complex moiety at pseudo axial and equatorial positions leads to respective TS 8a’ and 8a”, while 8a’ is more stable due to the minimization of the A[1,3] interaction. Therefore, it is observed 3a’ produced from corresponding 8a’ as the major diastereomer whereas 3a” as minor one.


Synergistic chiral iminium and palladium catalysis: Highly regio- and enantioselective [3 + 2] annulation reaction of 2-vinylcyclopropanes with enals
The proposed transition states.
© Copyright Policy - Beilstein
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4979765&req=5

C3: The proposed transition states.
Mentions: We proposed two possible transition states (TS) 8a’ and 8a” to rationalize the observed configurations (Scheme 3). The trans-C=C double bond in iminium ion 4 dictates the R group at pseudo axial position in the cyclic 5-membered ring TS 8a’ and 8a”. This orientation avoids the A[1,3] strain induced by the catalyst-derived enamine. The Pd(II)-π3 complex moiety at pseudo axial and equatorial positions leads to respective TS 8a’ and 8a”, while 8a’ is more stable due to the minimization of the A[1,3] interaction. Therefore, it is observed 3a’ produced from corresponding 8a’ as the major diastereomer whereas 3a” as minor one.

View Article: PubMed Central - HTML - PubMed

ABSTRACT

A cooperative catalytic strategy of chiral iminium catalysis by regioselective activation of the C=C bond in enals and a transition metal promoting to open the 2-vinylcyclopropanes for highly regio- and enantioselective [3 + 2] cycloaddition reaction of 2-vinylcyclopropanes with α,β-unsaturated aldehydes has been developed.

No MeSH data available.