Construction of Asymmetric Field Utilizing Atropisomers

具有异构性的化合物，如1，1‘-联萘衍生物，提供了一个有效的不对称环境。对称碳的手性中心没有柔韧性。另一方面，1，1‘-联萘衍生物的手性环境足够灵活，可以通过改变两个芳香平面之间的二面角来缓解或调节空间相互作用，而不改变手性的感觉。因此，1，1‘-联萘-2，2’-二醇(BINOL)被广泛用作不对称合成和手性识别的手性控制器。本研究的目的是设计新型的含萘环的阿托品异构体，并将其用于不对称分子识别。本研究包括两个方面的研究，即合成具有光学活性的二元醇结构单元的螺苯并吡喃衍生物和创造一种新型的阿托品异构体。螺苯并吡喃是已知的光致变色化合物，在紫外光下异构化为相应的花菁形式，在可见光或热下反之亦然。我们合成的化合物中有一种可以通过花菁形式显色的时间来区分氨基酸的光学异构体，如BINOL是由于单键的限制旋转所致。我们这项研究的目标是通过两个单键合成新的阿托品。我们合成了一些8位和8‘位取代的1，1’-联萘醚，结果表明，当取代基体积较大时，它们可以作为稳定的光学异构体存在。这些化合物被认为是最简单的分子锥齿轮，每个轮子上只有两个齿轮，齿轮的滑动会导致外消旋。

The compounds with atropisomerism, such as 1,1'-binaphthyl derivatives, provide an effective asymmetric environment. Symmetric carbons have no flexibility at their chiral center. On the other hand, chiral environment of 1,1'-binaphthyl derivatives is flexible enough to relieve or adjust the steric interaction by changing the dihedral angle between two aromatic planes without changing the sense of chirality. Therefore, 1,1'-binaphthalene-2,2'-diol (BINOL) has been extensively utilized as a chiral controller for asymmetric syntheses and chiral recognition. A purpose of this research is to design the new atropisomeric compounds with the naphthalene rings and to utilize these compounds for the asymmetric molecular recognition.This project includes two researches, namely synthesis of spirobenzopyran derivatives having optically active BINOL as a structural unit and creation a new type of atropisomerism. Spirobenzopyrans are known photochromic compounds that isomerize to their corresponding merocyanine forms under UV light, and vice versa under visible light or heat. One of the compounds we synthesized could discriminate the optical isomer of amino acids by the time of developing the color by the merocyanine form.The atropisomers such as BINOL are due to a restricted rotation of a single bond. Our goal of this research was to synthesize new atropisomers through two single bonds. We have synthesized a number of 1,1'-binaphthyl ethers substituted at 8-and 8'-positions and shown that they could exist as a stable optical isomer when the substituents were bulky. These compounds are regarded as the simplest molecular bevel gear possessing only two cogs on each wheel, the gear slippage of which results in racemization.