Diastereodifferentiating the [2+2] Photocycloaddition of Ethylene to Arylmenthyl Cyclohexenonecarboxylates: Stacking-Driven Enhancement of the Product Diastereoselectivity That Is Correlated with the Reactant Ellipticity

作者：Tsutsumi Ken; Yanagisawa Yuuki; Furutani Akinori; Morimoto Tsumoru; Kakiuchi Kiyomi^*; Wada Takehiko; Mori Tadashi; Inoue Yoshihisa

来源：Chemistry - A European Journal, 2010, 16(25): 7448-7455.

DOI：10.1002/chem.201000429

• chirality
• circular dichroism
• diastereoselectivity
• ethylene
• photocycloaddition

Upon diastereodifferentiating the [2+2] photocycloaddition of ethylene to a series of p-substituted (-)-8-phenylmenthyl cyclohexenone-carboxylates, the diastereoselectivity was critically controlled by the nature of the substituent introduced to the chiral auxiliary, and the p-nitro-substituted substrate afforded the cycloadducts in 90% diastereomeric excess (de) and with 97% isolated yield. Detailed experimental and theoretical conformation analyses the stacking interaction auxiliary with the revealed that of the aromatic cyclohexenone moiety plays the decisive role in determining the substrate conformation and is, therefore, responsible for the dramatic enhancement of the de. Of particular interest, the product de was directly related to the ellipticity of the substrate, enabling us to "predict" the de prior to photoirradiation.

• 出版日期2010