An Allylstannane Reagent on Non-Cross-Linked Polystyrene Support

Abstract

[reaction: see text] A new allylstannane reagent on non-cross-linked polystyrene was developed for the first time. This support differs markedly from standard cross-linked polymers because it is completely soluble in organic solvents; moreover, the reactions can be conveniently monitored directly by standard 1H NMR methods. The allylstannane underwent a free radical reaction with an alkyl halide to form a new allyl appendage. Tin byproducts can be easily recovered from cold methanol as white crystalline solids.

Ionic Liquid Supported Organotin Reagents: Green Tools for Stille Cross‐Coupling Reactions with Brominated Substrates

“…[2] However, the use of organotin reagents has been avoided for the synthesis of pharmacologically active substances due to their toxicity and the difficulties of removing residues from the products. As a result, ongoing efforts have been devoted to solve these problems by using solid-phase synthetic methods, [3,4] phosphonium-grafted organotins, [5] Stille couplings catalytic in tin, [6] and other modified organotin reagents. [7] Convenient access to biaryl compounds is receiving currently a great deal of attention due to the prominence of this scaffold in biological and naturally occurring molecules.…”

Non-cross-linked polystyrene-supported 2-imidazolidinone chiral auxiliary: synthesis and application in asymmetric alkylation reactions

“…Therefore, to save our 2-imidazolidinone chiral auxiliary, an alternative approach, in which the starting soluble polymer 4 was first prepared and then linked to 2-imidazolidinone chiral auxiliary 1 , was examined (Table 1 and Scheme 2) [6,12]. In an attempt to optimize the amount of loading sites in the soluble polymer and its solubility, several non-crosslinked chloromethylated polystyrenes 4 were simply synthesized according to reported procedures [6,8] in different feed ratios of 4-chloromethylstyrene and styrene of 1:1, 2:1, and 1:0 (Table 1).…”

“…In an attempt to optimize the amount of loading sites in the soluble polymer and its solubility, several non-crosslinked chloromethylated polystyrenes 4 were simply synthesized according to reported procedures [6,8] in different feed ratios of 4-chloromethylstyrene and styrene of 1:1, 2:1, and 1:0 (Table 1). The NCPS 4a , 4b , and 4c were obtained in 46, 40, and 52% yield, respectively, and showed also good solubility in THF, CH 2 Cl 2 , DMF, and benzene, and insolubility in methanol and water.…”

“…However, the unavoidable heterogeneous-phase reaction and the spectroscopic analysis of the functionally supported products are extremely problematic. In an attempt to bridge the gap between the solid phase and solution phase synthesis, non-cross-linked soluble polymer supports have attracted great interest because of some advantages such as high reactivity, easy analysis and purification of products [6–12]. …”

Use of polymer-supported phenyltin for the creation of aryl–aryl or aryl–heteroaryl bonds via Stille cross-coupling reactions

“…In addition, the concept of tin reagent grafted on a matrix has also been developed. This matrix can also be an imidazolium ionic liquid [32,33], a triarylphosphonium salt [34], a soluble polymer (which can be removed by precipitation) [35,36] or an insoluble macroporous polymer which can be separated by a simple filtration [37][38][39][40]. This last methodology is particularly well-suited for parallel and high-throughput syntheses which are widely developed for drug design in medicinal chemistry.…”