Catalyst-free dehydrocoupling of amines, alcohols, and thiols with pinacol borane and 9-borabicyclononane (9-BBN)

Abstract

Contrary to recent reports, the dehydrocoupling of pinacol borane and 9-borabicyclononane with a variety of amines, alcohols and thiols can be achieved under mild conditions without catalyst. This process involves the formation of Lewis acid-base adducts featuring a hydridic B-H in close proximity to an acidic Nu-H.

Borane Adducts of Hydrazoic Acid and Organic Azides: Intermediates for the Formation of Aminoboranes

“…[40] As expected, hydrolysis of 2H with aw ater/acetonitrile mixture led to the formation of the free amine H 2 N(C 6 F 5 ) (3H; Figure S21, Scheme 2), in addition to HC 6 F 5 and B(OH) 3 in good yields (yield of isolated substance = 72 %, m.p.358 8C). [42][43][44][45][46][47] Both compounds 1H·xyl and 2H crystallized in the triclinic space group P1, while 3H crystallized in the monoclinic space group Cc. [41] To gain further insight into the stability of azide-borane adducts,B (C 6 F 3 ) 3 was reacted with as eries of different covalently bound azides RN 3 (R = TMS (Me 3 Si), Ph, and Btp (3,5-(CF 3 ) 2 C 6 H 3 ;T able 1).…”

Hydroboration, Cyanosilylation, and Sequential Cyanosilylation and Hydroboration of Carbonyl Compounds in the Presence of a TiIV Amido Complex as an Efficient Catalyst

“…Yields were determined by 1 H NMR. [38] In addition, treatment of pyridine-2-carbaldehyde with HBpin led to the exclusive hydroboration of the carbonyl functionality instead of pyridine hydroboration (Table 3, Entry 6, FS 87-89 in the Supporting Information), as can be expected in view of the high oxophilicity of the titanium ion. The reactions between HBpin and pyrrole-2-carbaldehyde or pyrrole-2,5-carbaldehyde led to the hydroboration of the aldehyde functionalities (Table 4, Entries 3 and 5, FS 78-80 and 84-86 in the Supporting Information), thus avoiding the catalyst-free dehydro coupling of amines with boranes.…”

A Highly Effective Route to Si−O−Si Moieties through O‐Silylation of Silanols and Polyhedral Oligomeric Silsesquioxane Silanols with Disilazanes

“…[59] Therefore, it is highly desirable to reduce the amount of catalyst (or avoid its use), and to minimize waste generatedd uring the reaction. [63][64][65][66][67][68][69][70][71][72] Important advantages of many of thesem ethods are their simplicity and efficiency.I np articular,r oom-temperature (RT) reactions are very attractive for potential further application.G iven all this, we focusedo nd eveloping the synthesis of organosilicon compoundsi nagreen chemistry manner. [63][64][65][66][67][68][69][70][71][72] Important advantages of many of thesem ethods are their simplicity and efficiency.I np articular,r oom-temperature (RT) reactions are very attractive for potential further application.G iven all this, we focusedo nd eveloping the synthesis of organosilicon compoundsi nagreen chemistry manner.…”