Potassium tris hydroborate

A )-and (Z)-alkenylboranes, or the corresponding boronic esters or potassium tri-fluoroborates, are conveniently available via hydroboration of terminal alkynes or 1-halo-1-alkynes using either disiamylborane, dicyclohexylborane, dibromoborane dimethyl sulfide, or catecholborane as hydroborating agents. ... 

Sand-sodium base. See Sodium-sand base a-Santalene, 42 Sobering process, 118-119 Schiff bases. See Imines 9,10-Secosteroids (calciferols and tachysterols), 31-32, 34, 281-283, 289 Seebach-Frater alkylation, 27. AT-Selectride = potassium hydrotris(l-mcthylpropyl)borate(l —) (KBHBVl), 107 XS-Selectride 1 — potassium tris(l,2-dimethyl-propyl)hydroborate(l —) (KBHSiay), 107 Z-Selectride = lithium hydrotri (l-... 

Lithium tri(sec-butyl)hydroborate(l -) is a highly active reducing agent with exceptional stereoselectivity for reduction of ketones to alcohols.4 The potassium analog exhibits equal or greater stereoselectivity. 

Carboethoxymethylation. As in the carbonylation reaction cited above, the original two-carbon-atom homologation reaction of trialkylboranes with ethyl bromoacetate (2, 192-193) had the defect that only one alkyl group of the tri-alkylborane is utilized. This disadvantage has now been eliminated by use of 9-BBN as the hydroboration reagent. Thus the B-alkyl-9-borabicyclo[3.3.1] nonane (B-R-9-BBN, 2), prepared as above, reacts with ethyl bromoacetate under the influence of potassium f-butoxide to give the homologated ester (3) in... 

The potassium salt of the hexadentate tris[3- (4-tbutyl)-pyrid-2-yl -pyrazol-l-yl]hydroborate (TpBuPy) has been described together with the crystal structure of [La(N03)2(TpBuPy)].166... 

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