Samarium(iii) catalyzed synthesis of alkenylboron compounds via hydroboration of alkynes

Abstract

The homoleptic lanthanide complex Sm[N(TMS)2]3 is an efficient rare-earth catalyst for the hydroboration of alkynes to the corresponding alkenylboron compounds. Practical applications were demonstrated in a gram-scale synthesis and further...

Recent Advances in the Functionalization of Terminal and Internal Alkynes

“…In 2021, Chen and co‐workers elegantly developed the hydroboration of alkynes to afford alkenyl boron compounds (Scheme 23). [25] This transformation was carried out in the presence of homoleptic lanthanide complex Sm[N(TMS) 2 ] 3 (1 mol%) as the catalyst, 3 equiv. of HBpin in hexane at 100 °C for 24 h. Under the optimum conditions, alkynes bearing either electron‐donating or electron‐withdrawing substituents at para or meta positions showed good reactivity, and corresponding products were achieved in good to excellent yields.…”

Regio- and chemoselective hydroboration of terminal alkynes with pinacolborane catalyzed by organo rare earth metal complexes

“…In marked contrast to these great advances in the hydroboration reactions, the catalytic application of earthabundant rare earth metal catalyst for synthesizing alkenylborons remains relatively rare. 7,8 In comparison with transition metal and main group metal catalysts, rare-earth metal catalysts have distinguishing characteristics like strong Lewis acidity, stable oxidation state (3+), large ionic radii, multiple coordination number, and manipulative coordination environment, and have exhibited great performances in organic transformations and mechanism studies. 9 However, the catalytic application of rare earth metal catalysts in the hydroboration of terminal alkynes and hydroborons have been much less extensively studied.…”

“…1 The hydroboration of terminal alkynes with hydroborons such as pinacolborane (HBpin, pin = OCMe 2 CMe 2 O), catecholborane (HBcat, cat = OC 6 H 4 O) or bis(pinacolato)diboron (pin)B–B(pin) is the most efficient route for the synthesis of alkenylborons. 2–8 Various catalysts such as transition metal catalysts, 3 main group metal catalysts, 4 boranes, 5 and carboxylic acids 6 have been developed, generating a variety of alkenylborons with high regio- and stereoselectivity. In marked contrast to these great advances in the hydroboration reactions, the catalytic application of earth-abundant rare earth metal catalyst for synthesizing alkenylborons remains relatively rare.…”

“…In marked contrast to these great advances in the hydroboration reactions, the catalytic application of earth-abundant rare earth metal catalyst for synthesizing alkenylborons remains relatively rare. 7,8…”

Hexamethyldisilazane Lithium (LiHMDS)-Promoted Hydroboration of Alkynes and Alkenes with Pinacolborane

“…Moreover, lithium catalysts were well applied for the hydroboration reactions of aldehydes, ketones, imines, and other substrates . Based on our previous hydroboration studies, we herein present the results of our research on the catalytic hydroboration of alkynes and alkenes with hexamethyldisilazane lithium (LiHMDS) and HBpin (Scheme d).…”