Borines s. Boranes

Borines s. Boranes, Phosphite borines. Phosphorous triamide borines Borinic acid esters... 

B-Alkenyl-9-BBN A borane/borinate exchange takes place at remarkably low temperature (0° vs. ca. 100° for borates and boranes) when alkenyldicyclohexylboranes and S-methoxy-9-BBN are mixed together in THF. The S-alkenyl-9-BBN are not directly accessible by hydroboration of alkynes because formation of 2 1 adducts ( e/n-bisboryl derivatives) predominates. 

Ethereal butyllithium added under N2 to furan, stirred and refluxed 6 hrs., then a soln. of tri-n-pentylborane added gradually at room temp, by a syringe through a rubber septum, and the product isolated after 1 hr. cyclic borinate (Y 65% based on the startg. borane) treated 5 hrs. at room temp, with 3 N NaOH and 30%-H202 4-n-pentyl-2-nonene-l,4-diol (Y ca. 100%). F. e. s. A. Suzuki, N. Miyaura, and M. Itoh, Tetrahedron 27, 2775 (1971). 

A mixture of triisobutylborane, o-tolyl borate, and borane in tetrahydrofuran stirred 2 hrs. at 100° under Ng, cooled, pentane added followed by 1-pentene and LiAlH4 in ether at 0°, stirred 0.5 hr. at this temp., then ice-cold NaOH-soln. added diisobutyl-n-pentylborane. Y 85%. Also isolation of the intermediate o-tolyl diisobutylborinate (Y 84%), and f. borinic acid esters as well as borinic acids s. H. C. Brown and S. K. Gupta, Am. Soc. 95, 2802 (1971). 

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