A Bithiophene‐Promoted ppm Levels of Palladium‐Catalyzed Regioselective Hydrosilylation of Terminal Allenes

Abstract

A bithiophene−alkyne‐based compound was synthesized and first utilized as a ligand for the selective hydrosilylation of allenes with primary and secondary phenylsilanes. It shows high selectivity towards the production of branched allylsilanes with a wide range of allenes. It is worth mentioning that the catalytic loading of the palladium can be reduced to 500 ppm. This work opens a new front of using bidentate thiophene ligand as a reaction promoter in transition‐metal‐catalyzed organic reaction.

A Versatile Palladium Synthon: [Pd(NHC)(PhC≡CPh)]**

“…However, they relied on a high loading of 5 mol% Pd 2 (dba) 3 (that is 10 mol% Pd) with 10 mol% IMes⋅HCl and 10 mol% of the strong base KO t Bu (Table 1)Tafazolian and Schmidt later used the well‐defined [Pd(3IP)(allyl)]OTf species in 1 mol% loading and without the use of a base to access allylsilanes (Table 1). [29b] This strategy has worked exceedingly well for primary and secondary silanes, however when it comes to tertiary silanes, the major product remained the vinylsilanes or very poor selectivities were observed [29c–e] …”

Regiodivergent hydroallylation of 1,3-diynes controlled by nickel and palladium catalysts

“…8 We wished to achieve hydroallylation of silyl-substituted diynes to synthesize the valuable 1,3-enynylsilane scaffold. Based on our previous result and literature research, 7,9 we made a great effort to explore the reaction. Encouragingly, when we chose allylB(pin) as the substrate and Pd 2 (dba) 3 /xantphos as the catalyst system, 1a 2 reacted smoothly to afford the unexpected α-selective allylic-substituted 1,3-enynylsilane product 3a , albeit with poor regioselectivity (Table 2, entry 1), differing from the Ni-catalyzed hydroallylation.…”

Ligand-Controlled Regiodivergent Hydrosilylation of Conjugated Dienes Catalyzed by Mono(phosphine)palladium(0) Complexes

“…Palladium-catalyzed hydrosilylation is an important strategy for the synthesis of organosilanes, and recently several progresses of palladium-catalyzed hydrosilylation of various alkenes were reported . On the other hand, although Pd complexes having phosphine ligands have long been known as a catalyst for Markovnikov-selective hydrosilylations, the low catalytic activity has been a problem.…”