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11.
Preparation of ammonia borane in high yield and purity, methanolysis, and regeneration 总被引:3,自引:0,他引:3
Ammonia borane (AB) is emerging as a promising solid hydrogen carrier, particularly for power generation in portable devices that employ proton-exchange membrane fuel cells. A preparative-scale synthesis of AB from sodium borohydride and ammonium salts in high yields (> or =95%) and very high purity (> or =98%) has been described. The first systematic study of a transitional metal-catalyzed alcoholysis of AB, comparison of the methanolysis to the hydrolysis of AB, and regeneration of AB from ammonium tetramethoxyborate also has been described. 相似文献
12.
Multi-substituted tetrahydropyrans (THPs) have been prepared via a one-pot, In(OTf)3-catalyzed, sequential allyl-/crotylboration-Prins cyclization. The homoallylic borate intermediate formed during the allyl- and crotylboration was converted in situ to an oxocarbenium ion and trapped with a nucleophile. The reaction has been extended to include a one-pot allylboration-cross Prins cyclization as well. 相似文献
13.
A novel and convenient one-pot asymmetric synthesis of 2- and 2,3-disubstituted tetrahydrofurans has been achieved in 56-81% yields and 86-99% ee from aliphatic and aromatic aldehydes via an allyl/crotyl/alkoxyallylboration-hydroboration-iodination-cyclization reaction sequence. 相似文献