Development of Highly Selective Reducing Reagent Which is Useful in Organic Synthesis

二异丁基氢化铝(DIBAH)是一种广泛使用的还原剂，它与α、β-不饱和羰基化合物反应生成烯丙醇。我们发现，六甲基磷三酰胺(HMPA)配体改变了DIBAH的还原活性，从而实现了&lt；α&gt；，&lt；β&gt；-不饱和羰基化合物的共轭还原，而甲基铜催化剂提高了DIBAH-HMPA的共轭还原活性。Mecu-DIBAH-HMPA体系可以选择性、高效地还原多种不饱和羰基化合物(醛、酮和酯)。Mecu-DIBAH-HMPA体系影响孕酮和角甲基化水杨二酮的立体选择性反式还原。后一种还原方法提供了一种制备成角度甲基化的反式稠合金刚环的方便方法。铜化合物的种类控制着共轭还原反应的立体选择性，而HCU-DIBAH-HMPA体系主要生成顺式稠合氢化吲哚。~lt；α&>t；，&lt；α&>t；，&lt；α&gt；，&lt；β&gt；-不饱和腈的还原可以在没有HMPA的情况下被Mecu-DIBAH体系实现。因此，我们已经能够开发出一种新型的，化学和立体选择性的Mecu-DIBAH-HMPA还原剂，它在有机合成中是有用的。

Diisobutylaluminum hydride (DIBAH) is a widely employed reducing reagent, which reacts with <alpha> , <beta> -unsaturated carbonyl compounds to produce allylic alcohols. We have found that the hexamethylphosphoric triamide (HMPA) ligand changes the reducing reactivity of DIBAH to effect the conjugate reduction of <alpha> , <beta> -unsaturated carbonyl compounds without the carbonyl reduction and the methylcopper-catalyst enhances the reactivity of the conjugate reduction by DIBAH-HMPA. The selective and efficient conjugate reduction of a variety of <alpha> , <beta> -unsaturated carbonyl compounds (aldehydes ketones, and esters) can be accomplished by MeCu-DIBAH-HMPA.The MeCu-DIBAH-HMPA system effects the stereoselective trans conjugate reduction of progesterone and angularly methylated hydrindenone. The latter reduction provides a convenient method of preparing angularly methylated trans fused hydrindane ring. The kind of the copper compound controles the stereoselectivity of the conjugate reduction, and the HCu-DIBAH-HMPA system gives predominantly the cis fused hydrindanone. The <alpha> , <beta> -reduction of <alpha> , <beta> -unsaturated nitriles can be effected by the MeCu-DIBAH system without HMPA.Thus, we have been able to develope a novel, chemo- and stereoselective reducing reagent of MeCu-DIBAH-HMPA which is useful in organic synthesis.