Straightforward Iron‐Catalyzed Synthesis of Vinylboronates by the Hydroboration of Alkynes

Abstract

An iron‐catalyzed hydroboration of alkynes to produce vinylboronates has been examined. With a straightforward system composed of iron carbonyls and pinacolborane, good to excellent yields and chemoselectivities were achieved for a variety of alkynes.

Recent Advances in Hydrometallation of Alkenes and Alkynes via the First Row Transition Metal Catalysis

“…[284] Subsequently, the same group found iron catalyst could enable efficient and regioselective C-C cleavage of vinylcyclopropanes with a modified OIP ligand (126), delivering (E)-alkenes with high stereospecific selectivity at the allylic position (Scheme 102b). [285] This protocol exhibited mild conditions with good functional group tolerance to prepare chiral homoallylic organoboronic esters, which could be further converted into chiral polysubstituted tetrahydrofuran and tetrahydropyran.…”

Hydroboration of Alkenes and Alkynes Employing Earth‐Abundant Metal Catalysts

“…Relatively low conversion (30%) was observed when the reaction was carried out at room temperature. However, it is noteworthy that product formation occurred with exclusively trans ‐selectivity, similar to the selectively observed in hydroboration of alkynes by groups of Enthaler and Nishibayashi . The conversion improved upon increasing the reaction temperature to 70 °C, although extended reaction times were necessary to achieve modest conversion (24 h, 60%).…”

“…In the past decade, a number of iron‐based catalysts have been developed as effective catalysts in the hydroboration of C−C multiple bonds using both HBpin and B 2 pin 2 (pin=pinacolato) (Figure ). In 2013, Enthaler and co‐workers reported the first example of an iron‐catalyzed hydroboration of alkynes . Chirik and co‐workers employed a bis(imino)pyridine iron dinitrogen complex, ( iPr PDI)Fe(N 2 ) 2 to catalyse the hydroboration of alkenes to afford linear boronate ester products .…”

Iron Catalysis II

“…of HBpin at 100 C for 24 h. Starting from terminal alkynes, under similar conditions, (E)-vinylboronate derivatives were obtained selectively (17 examples), whereas more complex mixtures of regioisomers were obtained starting with terminal alkynes [205]. Using FeCl 3 or np Fe 3 O 4 (5 mol%) in the presence of 1.2 equiv.…”