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首页> 外文期刊>Organometallics >Can a Butadiene-Based Architecture Compete with its Biaryl Counterpart in Asymmetric Catalysis? Enantiopure Me-CATPHOS, a Remarkably Efficient Ligand for Asymmetric Hydrogenation
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Can a Butadiene-Based Architecture Compete with its Biaryl Counterpart in Asymmetric Catalysis? Enantiopure Me-CATPHOS, a Remarkably Efficient Ligand for Asymmetric Hydrogenation

机译：基于丁二烯的体系结构在不对称催化中能否与联芳基竞争？ Enantiopure Me-CATPHOS，非对称加氢的高效配体

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摘要

The double Diels-Alder cycloaddition between 9-methylanthracene and 1,4-bis(diphenylphosphinoyl)buta-1,3-diyne affords the oxide of the atropos diphosphine, Me-CATPHOS, which has an unusual bicyclic buta-1,3-diene-based architecture. Quantum chemical methods using DTF reveal that the barrier to atropinterconversion in Me-CATPHOS is 130 kJ mol(-1), while the corresponding barrier for its unsubstituted counterpart is only 23 kJ mol-1, entirely consistent with the former being an atropos diphosphine while the latter belongs to the tropos class of ligand. rac-Me-CATPHOS can be resolved by fractional crystallization of the diasteresomeric complexes formed with (2R,3R)-(-)-2,3-O-dibenzoyltartaric acid and reduction of the resulting enantiopure oxide, accomplished by silane reduction in xylene at 130 degrees C, to afford an operationally straightforward, three-step synthesis of an entirely new class of atropos buta-1,3-diene-based diphosphine. Rhodium complexes of enantiopure Me-CATPHOS catalyze the asymmetric hydrogenation of a range of dehydroamino acid derivatives, in some cases giving ee's in excess of 99% and in all cases showing a significant enhancement compared with its BINAP counterpart. Gratifyingly, Rh/(S)-Me-CATPHOS outperforms all existing catalysts for the asymmetric hydrogenation of (E)-beta-dehydroamino phosphonates, many of which are based on markedly more expensive biaryl- and ferrocenyl-based diphosphines. Surprisingly, in the case of the dehydroamino acid substrates, (S)-Me-CATPHOS provides product of opposite absolute stereochemistry to that obtained with (S)-BINAP, despite both ligands having an S-ax configuration, whereas (S)-Me-CATPHOS exerts (S)-BINAP-like stereoinduction for the hydrogenation of beta-enamidophosphonates; both ligands afford product with the same absolute configuration.
机译：9-甲基蒽与1,4-双（二苯基膦酰基）丁1,3-二炔之间的双Diels-Alder环加成反应可得到atropos二膦Me-CATPHOS的氧化物，后者具有不同寻常的双环丁1,3-二烯基于架构。使用DTF的量子化学方法显示，Me-CATPHOS中对atropinterconversion的障碍是130 kJ mol（-1），而其未取代对应物的相应障碍仅为23 kJ mol-1，与前者是atropos二膦而完全一致后者属于配体的对等类别。 rac-Me-CATPHOS可以通过分步结晶与（2R，3R）-（-）-2,3-O-二苯甲酰基酒石酸形成的非对映异构体配合物并还原生成的对映纯氧化物来解决，方法是通过在20 130摄氏度，以提供一种全新的基于atropos丁1,3-二烯的二膦类化合物的操作简便，三步合成的方法。对映体纯Me-CATPHOS的铑配合物催化一系列脱氢氨基酸衍生物的不对称氢化，在某些情况下，ee的99％以上，在所有情况下，与BINAP对应物相比，均显示出显着增强。令人欣慰的是，Rh /（S）-Me-CATPHOS优于所有现有的（E）-β-脱氢氨基膦酸酯不对称加氢的催化剂，其中许多是基于价格更为昂贵的基于联芳基和二茂铁基的二膦。令人惊讶地，在脱氢氨基酸底物的情况下，尽管两个配体均具有S-ax构型，但是（S）-Me-CATPHOS提供与用（S）-BINAP获得的绝对立体化学相反的绝对立体化学的产物，而（S）-Me -CATPHOS发挥（S）-BINAP样的立体诱导作用，以氢化β-烯酰胺膦酸酯;两种配体均提供具有相同绝对构型的产物。

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