Lithium diisobutyl-n-butylaluminum hydride, the "ate" complex generated from diisobutylaluminum hydride and n-butyllithium in an equimolar ratio, was reacted with a series of selected organic compounds containing various functional groups in order to explore the reducing properties and to determine the synthetic utility of the reagent. The reagent exhibits excellent stereoselectivties in the reduction of sterically hindered cyclohexanones and bicyclic ketones to give thermodynamically less stable alcohols. The reagent was very effective for selective 1,2-reduction of both acyclic and cyclic enones. The reagent rapidly reduces simple primary alkyl, benzyl, and allyl bromides but slowly primary alkyl chlorides and secondary alkyl bromides. Tertiary alkyl and aryl halides are essentially inert to the reagent. Esters and lactones are completely reduced to the corresponding alcohols at room temperature, whereas they are reduced to the corresponding alcohols and aldehydes at -78℃ even with an excess amount of the reagent. Acid chlorides and acid anhydrides are rapidly reduced to the corresponding alcohols and an equimolar mixture of the acid and the alcohol at -78℃, respectively. Carboxylic acids and primary and secondary amides are inert to the reagent at room temperature. Tertiary amides are cleanly reduced to the aldehydes with a stoichiometric amount of the reagent either at 0℃ or at room temperature, whereas they are inert to the reagent at -78℃. Epoxides are cleanly reduced to the corresponding alcohols in excellent isomeric purity. Nitriles are resistant to reduction and are only slowly converted to the corresponding aldehydes at room temperature. Disulfides are rapidly reduced to the corresponding thiols. Sulfoxides and sulfones are inert to the reagent. Selective reduction of an ester in the presence of a bromide, a tertiary amide, and a nitrile are achieved with the reagent at -78℃ by using a modified procedure. Furthermore, the reagent is capable of reducing selectively a ketone in the presence of an ester.
Several synthetic approaches for the synthesis of (+)-acaranoic acid using methyl α-D-glucopyranoside as a chiral template were investigated.
A key intermediate (31) was synthesized in an overall high yield from the known compound (5) via deoxygenation of the hydroxyl group at $C_4$, carbon-carbon bond formation by Wittig reaction, and introduction of nitromethyl group, equivalent to an carboxymethyl group, at $C_3$. In addition several important intermediates were prepared and characterized.
디이소부틸 n-부틸 수소화 알루미늄산 리튬의 여러가지 작용기를 가지는 일련의 유기 화합물에 대한 환원 성질과 합성에의 유용성에 대해 연구하였다. 이 환원제는 입체 장애가 있는 시클로헥산온 유도체와 비시클로케톤에 대해 탁월한 입체 선택성을 보여 열역학적으로 불안정한 알코올을 주된 생성물로 준다. 또한 $\alpha,\beta-$불포화케톤에 대해 매우 우수한 지역 선택성을 보여 대응하는 알릴알코올로 환원한다. 일차 알킬, 벤질, 그리고 알릴 브로모 화합물을 빠르게 환원하며, 일차 알킬클로로화합물과 이차 알킬 브로모 화합물은 반응 않는다. 에스테르와 락톤은 상온에서 알코올로 환원되나, $-78\,^\circ\!C$에서는 과량의 환원제에 의해서도 대응하는 알코올과 알데히드로 환원된다. 염화아실과 카르복시산 무수물은 $-78\,^\circ\!C$에서 각각 알코올과 그리고 카르복시산과 알코올의 1:1 혼합물로 환원된다. 카르복시산과 일차 및 이차 카르복시아미드는 상온에서도 반응 않는다. 삼차 카르복시아미드는 $0\,^\circ\!C$ 혹은 상온에서 정량의 환원제에 의해 대응하는 알데히드로 환원되나, $-78\,^\circ\!C$에서는 반응 않는다.
에폭시화합물은 환원되어 한 이성질체가 높은 비율로 생성된다. 니트릴은 느린 속도로 알데히드로 환원되나 술폭시화물과 술폰은 반응하지 않는다. 이 환원제는 브로모, 3차 카르복시아미드, 그리고 니트릴 화합물 존재하에서 에스테르를 선택적으로 환원하며, 나아가 에스테르 존재하에서 케톤을 선택적으로 환원할 수 있다.
