利用環糊精研究對苯昆Diels-Alder反應的方位選擇性

Abstract

在水溶液中利用不對稱雙烯和不同取代的對苯昆於環糊精水溶液中進行 Diels-Alder 反應，利用環糊精孔洞的立體效應來達到較佳或相反於有機 溶劑中的方位選擇性。相對於水及有機溶劑，在環糊精水溶液中的反應速 率有明顯的加速作用。1H NMR光譜法提供了產物與環糊精可以形成錯合物 的資訊。 Diels-Alder reaction of several substituted para-quinones with piperylene and isoprene were studied in aqueous solution in the presence and absence of cyclodextrins. An enhanced or reversed regioselectivity was achieved by the " cavity control " of cyclodextrins compared to that in organic solvents. Notably, reactions run in aqueous beta-CD solution are highly accerated compared to that in water. 1H NMR spectroscopy provides evidences to support the inclusion complex formation of Diels- Alder adducts with CDs.