Diboron reagents tetra

Therefore, this historical prospection toward the activation of diboron has moved from direct reaction of CI2B—BCI2 with alkenes to the current methodology that circumvent the activation of tetra(alkoxy)diboron reagents with simple LBs. But metal activation has been and still is a... 

The same reaction produced different alkenes 58-6563 (Scheme 13). These reactions were not catalyzed by rhodium(I) or palladium(0). Tetra(methoxo)- and bis(pinacolato)diboron(4) added to both terminal and internal alkynes in the presence of a catalytic amount of Pt(PPh3)4 to provide stereo defined pinacolato r/s-bis(boryl)alkenes 58-65 in excellent yields. Because reagents and reaction conditions were sufficiently mild,... 

This method is an adaption of the U. S. Borax Research group s procedure that Illustrates a practical and efficient method for the synthesis of tetra(alkoxo)diborons. Several (alkoxo)diborons, such as tetra(methoxo)-,3 bis(catecholato)-, and bis(pinacolato)diboron (1). are synthesized from tetrakis(dimethylamino)diboron. The diborons are excellent reagents for the synthesis of various organoboronic esters via the transition metal-catalyzed addition and cross-coupling reactions. ... 

It seems that all the efforts to activate tetra(alkoxy)diboron compounds are justified since the model CI2B—BCI2 reagent, which develops borylation without metal activation, is too difficult to handle. However, the progress in this field has opened a new window toward the activation of tetra(alkoxy) diboron compounds in a metal-free context by the formation of Lewis add—base adducts and their addition to unsaturated substrates can be performed with total chemo-, regjo-, and stereoselectivity. 

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