Reaction mechanism of transmetalation between tetraorganostannanes and platinum(II) aryltriflate complexes. Mechanistic model for stille couplings

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Reaction mechanism of transmetalation between tetraorganostannanes and platinum(II) aryltriflate complexes. Mechanistic model for stille couplings. / Nilsson, Patrik; Puxty, G; Wendt, Ola.

In: Organometallics, Vol. 25, No. 5, 2006, p. 1285-1292.

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TY - JOUR

T1 - Reaction mechanism of transmetalation between tetraorganostannanes and platinum(II) aryltriflate complexes. Mechanistic model for stille couplings

AU - Nilsson, Patrik

AU - Puxty, G

AU - Wendt, Ola

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Organic chemistry (S/LTH) (011001240), Department of Chemistry (011001220)

PY - 2006

Y1 - 2006

N2 - The complexes trans-[PtPh(OTf)(PMe2Ph)(2)] (1) and trans- [PtPh(OTf)(PPh3)(2)] (4) were synthesized from the corresponding chloro complexes in moderate yields. Complex I is slowly hydrolyzed in solution, giving the dinuclear hydroxo-bridged complex [Pt(mu-OH)(PMe2Ph)(2)](2)(CF3SO3)(2) (6), which was characterized by X-ray crystallography. In solution I and 4 undergo fast solvolysis to give the corresponding solvento cations. The reactivities of 1 and 4 with Me3SnPh were investigated in different solvents, and with 1 two products, trans- [PtPh2(PMe2Ph)(2)] (8) and cis-[PtPh2(PMe2Ph)(2)] (9), were always formed simultaneously. In THF an intermediate, trans- [PtPhMe(PMe2Ph)(2)] (14), was characterized on the path to 9. The kinetics for these reactions were evaluated numerically, and on the basis of rate laws, activation parameters, and reactivity trends a mechanism involving parallel equilibria to 8 and 9 with associative activation in all steps is proposed. In this mechanism the initial attack always takes place trans to the phenyl group, giving 8 and 14, respectively, via an open transition state. In a subsequent reaction, 14 reacts with another molecule of stannane, giving 9 as the final product via a cyclic transition state. Complex 4 gives exclusive formation of cis products: cis-[PtPhMe(PPh3)2] (12) and cis-[PtPh2(PPh3)2] (13). These results are discussed in relation to the reaction mechanism of the transmetalation step in the Stille reaction.

AB - The complexes trans-[PtPh(OTf)(PMe2Ph)(2)] (1) and trans- [PtPh(OTf)(PPh3)(2)] (4) were synthesized from the corresponding chloro complexes in moderate yields. Complex I is slowly hydrolyzed in solution, giving the dinuclear hydroxo-bridged complex [Pt(mu-OH)(PMe2Ph)(2)](2)(CF3SO3)(2) (6), which was characterized by X-ray crystallography. In solution I and 4 undergo fast solvolysis to give the corresponding solvento cations. The reactivities of 1 and 4 with Me3SnPh were investigated in different solvents, and with 1 two products, trans- [PtPh2(PMe2Ph)(2)] (8) and cis-[PtPh2(PMe2Ph)(2)] (9), were always formed simultaneously. In THF an intermediate, trans- [PtPhMe(PMe2Ph)(2)] (14), was characterized on the path to 9. The kinetics for these reactions were evaluated numerically, and on the basis of rate laws, activation parameters, and reactivity trends a mechanism involving parallel equilibria to 8 and 9 with associative activation in all steps is proposed. In this mechanism the initial attack always takes place trans to the phenyl group, giving 8 and 14, respectively, via an open transition state. In a subsequent reaction, 14 reacts with another molecule of stannane, giving 9 as the final product via a cyclic transition state. Complex 4 gives exclusive formation of cis products: cis-[PtPhMe(PPh3)2] (12) and cis-[PtPh2(PPh3)2] (13). These results are discussed in relation to the reaction mechanism of the transmetalation step in the Stille reaction.

U2 - 10.1021/om051021a

DO - 10.1021/om051021a

M3 - Article

VL - 25

SP - 1285

EP - 1292

JO - Organometallics

JF - Organometallics

SN - 1520-6041

IS - 5

ER -