Polymeric Reagents with Propane-1,3-dithiol Functions and Their Precursors for Supported Organic Syntheses

Abstract

Reliable completely odorless syntheses of soluble copolymeric reagents of styrene type containing propane-1,3-dithiol functions able to convert carbonyl compounds into 1,3-dithiane derivatives and to support other useful transformations are reported together with their progenitor copolymers containing benzenesulfonate or thioacetate groups perfectly stable in open air and suitable for unlimited storage. The effectiveness of the prepared reagents as tools for polymer-supported syntheses to produce ketones by aldehyde umpolung and alkylation is tested in the conversion of benzaldehyde to phenyl n-hexyl ketone starting from copolymers with different contents of active units and molecular weights. To facilitate the adaptation of the prepared soluble copolymeric reagents to other possible applications, a table of solvents and nonsolvents is presented.

Synthesis of Model Molecules and NMR Analysis of Polymeric Reagents Based on Propane-1,3-dithiol and 1,3-Dithiane Systems

“…The copolymer P1, prepared from 1 and styrene under conditions that ensure a monomer content in the copolymer Scheme 1 Scheme 2 not diverging by more than 0.5% from that of the feed [7] (see Exp. Sect.…”

“…Styrene, azo bis-isobutyronitrile (AIBN) and solvents were treated as reported elsewhere. [7] Monomer 1 was prepared according to a previous study. [6] Soluble copolymers P1ϪP4 were prepared as previously described.…”

“…[6,7] In this paper we report a detailed 1 H and 13 C NMR study of our reagents and of purposely made model molecules, with the aim of designing simple methodologies for the control of their future preparations and applications.…”

Ein Phosphoran als polymergebundenes Acylanionenäquivalent: Linkerreagentien für schonende und vielseitige C‐C‐Kupplungen

“…[6,7] Für die Ausführung komplexerer Reaktionssequenzen unter Beteiligung von C-C-Kupplungen wären polymergebundene Carbanionenäquivalente eine ideale Ergänzung des präparativen Repertoirs der polymerunterstützten Synthese. Über lithiierte Dithioacetale [8][9][10] als polymergebundene Carbanionenäquivalente wurde berichtet; diese Reagentien sind jedoch stark basisch und deshalb für die effiziente Parallelsynthese empfindlicher Produkte unbrauchbar. Idealerweise sollte die gesuchte Methode Reaktionen mit leicht verfüg-baren Synthesebausteinen unter schonenden, neutralen Bedingungen und eine Weiterderivatisierung im Anschluss an die C-C-Kupplung ermöglichen.…”

A Phosphorane as Supported Acylanion Equivalent: Linker Reagents for Smooth and Versatile CC Coupling Reactions

“…[6,7] To establish more complex reaction sequences including C À C coupling steps, polymer-supported carbanion equivalents would be an ideal addition to the synthetic repertoire in polymer-assisted synthesis. Lithiated dithioacetals [8][9][10] have been described as polymer-supported carbanion equivalents, however, these reagents are strongly basic and are thus of no use for the efficient parallel synthesis of sensitive products. Ideally, the successful method should allow reactions with easily available building blocks, under smooth, neutral conditions, and further derivatization after the CÀC coupling step.…”