Sodium tris hydroborate

The required working time is 3 to 4 hours. All equipment is thoroughly dried prior to use and is flushed with an inert gas (argon or nitrogen). Commercial sodium hydroborate is used without purification. The dimethyl ether of diethylene glycol (diglyme) is refluxed over calcium hydride for 8 hours and subsequently distilled over lithium tetrahydroaluminate (lithium aluminum hydride). Commercial tri-n-butylamine is refluxed with acetic anhydride and distilled at atmospheric pressure. 

Commercially available solutions of H3B-THF in THF (Aldrich-Boranes, Inc., 2371 N. 30th St., Milwaukee, WI 53210) which are used in this synthesis, contain approximately 5% of sodium tetrahydroboratefl —) as a stabilizer. Tri(sec-butyl)borane prepared from these solutions should be distilled. An alternative commercial (Aldrich-Boranes, Inc.) hydroborating agent free of sodium tetrahydroborate(l —) is borane-methyl sulfide. 

Hydroboration of 1-methylcyclopentene (1) with diborane gives tris-(frans-2-methyl-cyclopentyl)borane (2), which on oxidation gives tra/is-2-methylcyclopentanol (3).1 Addition of sodium cyanide to a solution of (2), followed by treatment with trifluoro-acetic anhydride (TFAA) and then by oxidation with alkaline hydrogen peroxide, gives... 

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-... 

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