Hydrosilylation Reactions of 1,3-Diynes and Bis(silyl hydrides):  Model Studies and Polymerizations

Abstract

The first examples of polymers made from the bis-hydrosilylation reaction of 1,3-diynes and bis-silylhydrides are reported. These polymers exhibit modest molecular weights and possess a cis,cis-2,3-disubstituted-1,3-butadiene structure as determined NMR analysis of model compounds. SEC and MALDI analysis of reaction mixtures suggest that cyclic dimers and higher order oligomers are also formed. Model reactions indicate that very sterically hindered diynes or silyl hydrides give only the 1,3-eneyne mono-addition products.

Iridium-catalyzed Markovnikov hydrosilylation of terminal alkynes achieved by using a trimethylsilyl-protected trihydroxysilane

“…The bulky (TMSO) 3 SiH, which is easily prepared from HSiCl 3 and (TMS) 2 O, was chosen as the silane partner to verify our anticipation. It is noteworthy that though in contrast with the wide utilization of Et 3 SiH, (EtO) 3 SiH and other common hydrosilanes in hydrosilylation of unsaturated molecules, examples that use (TMSO) 3 SiH as hydrosilane source are still limited [58][59][60][61][62][63][64] , it showed its unique function in promoting the reaction selectivity 63 or inducing different selectivities 64 . Several simple iridium catalysts were tested firstly under a mild condition (entry 1-4).…”

Hydrosilylation of Diynes as a Route to Functional Polymers Delocalized Through Silicon

“…This was the first example of the use of steric hindrance to control the hydrosilylation reactivity. More recent studies by Hensler et al have been devoted to the hydrosilylation of 1,3‐diynes (Scheme ) 50. The increased steric freedom in these systems creates a pathway for the formation of many isomers.…”

Selective Hydrosilylation of Dienes, Enynes, and Diynes Catalyzed by a Platinum Complex with a Very Bulky NHC Ligand – The Crucial Role of Precise Tuning of the Reaction Conditions

“…The literature describing selective transformations of polyunsaturated reagents is scarce and provides several examples of selective 1,4‐hydrosilylation and 1,2‐hydrosilylation[6b], of 1,3‐dienes. There are also reports describing significant selectivity in hydrosilylation of 1,4‐disubstituted 1,3‐enynes and 1,3‐diynes . Conjugated 1,3‐enynes with terminal triple bond, with 1‐ethynylcyclohex‐1‐ene as a typical example were shown to preferably undergo anti‐Markovnikov hydrosilylation of triple bond …”