149832-59-7Relevant articles and documents
Organogermanium(II) Hydrides as a Source of Highly Soluble LiH
Deraet, Xavier,Dostál, Libor,Jambor, Roman,R??i?ka, Ale?,Tremmel, Jakub,Turek, Jan,Tydlitát, Ji?í
, (2020)
The reactions of monomeric C,N-chelated organogermanium(II) hydride L(H)Ge?BH3 with organolithium salts RLi yielded lithium hydrogermanatoborates (Li(THF)2{BH3[L(H)GeR]})2. Compound (Li(THF)2{BH3[L(H)GePh]})2 was used as a source of LiH for the reduction of organic C=O or C=N bonds in nonpolar solvents accompanied by the elimination of a neutral complex L(Ph)Ge?BH3. The interaction of (Li(THF)2{BH3[L(H)GePh]})2 with the polar C=O bond was further investigated by computational studies revealing a plausible geometry of a pre-reactive intermediate. The experimental and theoretical studies suggest that, although the Li atom of (Li(THF)2{BH3[L(H)GePh]})2 coordinates the C=O bond, the GeH fragment is the active species in the reduction reaction. Finally, benzaldehyde was reduced by a mixture of L(H)Ge?BH3 with PhLi in nonpolar solvents.
Method for preparing organic borate compound
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Paragraph 0020; 0021; 0022; 0023-0029; 0046-0047; 0081-0082, (2017/07/21)
A method for preparing an organic borate compound relates to organic borate compounds, and is characterized in that a catalyst, a carbonyl compound or an alkynes compound and a boron hydride react in an organic solvent to obtain the organic borate compound, wherein the catalyst is an alkali metal hydroxide, which is selected from sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and is preferably sodium hydroxide. A carbonyl group or a terminal alkyne group can be efficiently reduced at a low price. As the low-price alkali metal hydroxide is taken as the catalyst, the boron hydride is catalyzed and selectively added to C-O dual bonds or C-C three bonds to obtain corresponding alkoxyl or alkenyl borate. The yield of the organic borate compound can be up to 99%. The prepared organic borate compound is suitable for aldehyde, ketone or alkynes compound substrates.
Trans-vinylboranes from 9-borabicyclo[3.3.1]nonane through dehydroborylation
Colberg, Juan C.,Rane, Anil,Vaquer, Jaime,Soderquist, John A.
, p. 6065 - 6071 (2007/10/02)
The hydroboration of 1-alkynes (1) was reinvestigated by 11B NMR under optimized conditions (THF, 18 h, 0°C) and found to provide trans-vinyl-9-BBN adducts (2) together with variable amounts of 1,1-diborylalkanes (3) depending both upon the excess of 1 employed and the nature of alkyne substitution. By contrast, the formation of 3 with 2 equiv of 9-BBN-H is quantitative. A new completely stereoselective route to 2 from 3 was discovered with its reaction with ArCHO in an electrocyclic process (p = 0.42). While analogous to the Midland reduction, the term dehydroborylation is introduced to emphasize the olefination aspect of the reaction. Compound 3a (R = Me) is smoothly dehydroborylated at 25°C with PhCHO following second-order kinetics. Competitive rate studies reveal its reaction to be slower than that of Alpineborane (7) (k7/k3a = 4.5) but faster than that of B-siamyl-9-BBN (6) (k6/k3a = 0.34). The value of the dehydroborylation approach to 2 and the advantages of using 9-BBN derivatives in vinylborane reactions are demonstrated with numerous examples. Thus, 1,8-nonadiyne is converted, through a bis(vinylborane) (11), to pure trans,trans-1,9-dideuterio-1,8-nonadiene (12). This transformation has not been previously possible for 9-BBN-H because of competitive dihydroboration. The dihydroboration of 1-(triethylsilyl)-1-propyne, after thermal isomerization and deuterolysis, affords trans-(3-deuterioallyl)silane (16), a most remarkable overall conversion. The insertion of aromatic aldehydes into 2 was further demonstrated to provide a convenient entry to trans-allylic alcohols. The selective oxidation of 2 with TMANO produces trans-alkenyl-9-oxa-10-borabicyclo[3.3.2]decanes, 18, which resist further reaction with ArCHO, oxidation in the atmosphere, and protonolysis. A 1→ 3 → 2 → 20 sequence was employed without the isolation of 2 in a one-pot Suzuki coupling with ArBr to provide trans-stilbenes (20, Ar = p-C6H4X, X = OMe (80%), NMe2 (60%)).
