Cationic rhodium complex-catalysed highly selective hydrosilylation of propynylic alcohols: a convenient synthesis of (E)-γ-silyl allylic alcohols

Abstract

Cationic rhodium complex-catalysed hydrosilylation of alk-l-ynols including propynylic alcohols with triethylsilane is highly selective to give (a-l -triethylsilyl alk-1 -enols as products in excellent yields.Neutral rhodium complex-catalysed hydrosilylation of alk-lynes gives (2)-vinylsilanes as the major product via the trans addition of Si-H across the carbon-carbon triple bond.1 In contrast to the extensive amount of the work on the neutral rhodium complex-catalysed hydrosilylation of alk-l-ynes, catalysis by cationic rhodium complexes has not been reported. In the course of the study of solvent effects on hydrosilylation, we noticed reversal of stereoselectivity for cationic rhodium complex catalysis, i. e. cationic rhodium complex-catalysed hydrosilylation of hex-l-yne with triethyl-

A Highly Chemoselective Cobalt Catalyst for the Hydrosilylation of Alkenes using Tertiary Silanes and Hydrosiloxanes

“…The hydrosilylation of 5-hexen-1-ol with Me 2 PhSiH (2p) and MD′M (3p) proceeded in similar fashion in 1,4-dioxane. Although tolerated with certain Pt and Rh catalysts, 27,28 to the best of our knowledge, alcohols have not been previously reported with cobalt hydrosilylation catalysts. Further elaboration of the catalyst's ability to tolerate oxygen-containing substrates led us to investigate the hydrosilylation of substrates bearing methoxy, allyl ether, and epoxide moieties (2q−s).…”

Addition of Metalloid Hydrides to Alkynes: Hydrometallation with Boron, Silicon, and Tin

“…A very bulky tertiary propargylic alcohol as well as a simple linear alkyne provide excellent access to the (E)-b-vinylsilane products. 61,63 However, the need for synthetically useful substituents on silicon limits the synthetic utility of most rhodium catalysts. 28 The significant success with (EtO) 3 SiH is noteworthy, and further analysis of substrate scope might lead to an extremely useful process.…”

Synthesis, Reactivity, Crystal Structures and Catalytic Activity of New Chelating Bisimidazolium‐Carbene Complexes of Rh

“…The progress of the reaction was monitored by 1 H NMR spectroscopy, according to the data of the products obtained from the literature. [28,30] Hydrogen-Transfer Catalysis: A mixture of the ketone (2 mmol), KOH (10 mL, 0.2  in iPrOH) and a suspension of 4 (0.06% or 0.006% mol vs. substrate) in CH 2 Cl 2 was heated to reflux. After the desired reaction times, aliquots were extracted from the reaction vessel and added to an NMR tube containing 0.5 mL of CDCl 3 .…”