我們以二環庚烯酮為骨架可合成一系列的環硫化合物及螺旋烯化合物，而且在其下盤苯環之C(2))位置引進L-menthol光學輔助基，但是在環硫化合物的de值只有16 %，而其相對的螺旋化合物de 值只有20 %。由氫譜上，發現環硫化合物C(2’)上Hax與Heq的位移有顯著的不同；Heq在較高磁場的位置(δ= 1.33-1.66 ppm)，主要是由於其剛好坐落在苯環(ArL)上方，受其環電流遮蔽效應所造成。在環硫化合物與螺旋烯化合物的對拆離，除了下盤為７環的螺旋烯例子外，我們都順利的以HPLC，配合Chiralcel AD管柱完成分離。對於環硫化合物的絕對立體化學結構，我們已歸納出其與CD上激發子掌性(exciton chirality)的關係。即由HPLC所先沖堤出的鏡像異構物，其絕對立體化學為具負向掌性的(S)-pro-(P)；而螺旋烯化合物絕對立體化學之判斷，則以HPLC所後沖提出的鏡像立體異構物為具負向掌性的P form螺旋。由此系列gλ和eepss的測量，我們預測其在利用長波長（>300mm）圓形極化光進行光學對拆離(photoresolution)時以下盤為單一苯環系統具有較佳誘導鏡像超越值（0.08%），此類光學開關(approach Ⅱ)比目前文獻上最好的系統稍差，但本系統在合成上更加簡便且結構上更行簡化，因而增加其實用性。將此最佳系統經對拆離後放入LC材料中進而測量βM（扭轉張力）發現，其效應是目前同類型系統的7到15倍。因此除了可將其添加量降至0.1%(w/w)以下外，更可在approach Ⅱ類型之光學開關由原約20%(w/w)的量降至<5%的實用層次上。由本系列中幾乎為0的量子產率說明以dibenzosuberenone為骨架之螺旋烯化合物的確相當容易進行光的雙鍵異構化，因此應能有效應用在光學記憶裝置及光學開關的開發上。

A series of episulfides and helicenes on the basis of dibenzosuberenone were synthesized and further resolved with a semi-preparative Chiralcel AD column of HPLC. The absolute configuration of the episulfides and that of helicenes were both determined by correlation of the exciton chiralities of CD spectra with those of (10R, 11R, S)-diethyl-dibenzosuberane-based episulfides of known absolute stereochemistry. However, the absolute configurations of the first eluted episulfides by chiral HPLC are (S)-pro-(P), but those of the first eluted helicenes are (M)-helicity. Furthermore, the helicenes derived from d-tetralone and chromanone analogs are found to display the best anisotropy factors (g) and induced ee pss (≧0.08%) under theoretical photoresolution irridiated at > 300 nm. This result parallels the best system from Feringa. But our helicenes are easier to assemble. Our best helicene was resolved and doped into a nematic LC (1% by weight). The measured twisting power (M) is about 7 to 15 times larger than those of Schuster’s helicenes of structural similarity. The negligible quantum yields of our helicenes strongly indicate that they are susceptible to photoisomerization and are potentially applicable to developments of optical memory devices and optical switches.

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