Role of Anions in the Synthesis of Cyclobutane Derivatives via [2 + 2] Cycloaddition Reaction in the Solid State and Their Isomerization in Solution
作者:Goutam Kumar Kole、Geok Kheng Tan、Jagadese J. Vittal
DOI:10.1021/jo201268p
日期:2011.10.7
made photoreactive by forming salts with various acids. The anions of these salts play a key role in directing the packing of 4-PAH+ in the solid state. The anions CF3CO2–, Cl–, ClO4–, and BF4– direct the parallel alignments of 4-PAH+ in head-to-tail (HT) fashion and lead to the formation of HT-photodimer. On the other hand, bivalent anion SO42– directs parallel alignment of 4-PAH+ in head-to-head (HH)
反式-3-(4'-吡啶基)丙烯酸(4-PA)在溶液和固态下均对光二聚反应呈惰性。通过与各种酸形成盐,使其具有光反应性。这些盐的阴离子在引导固态的4-PAH +堆积方面起着关键作用。阴离子CF 3 CO 2 - ,氯-,CLO 4 - ,和BF 4 -直接4- PAH的平行比对+在头-尾(HT)的方式,并导致HT-photodimer的形成。另一方面,二价阴离子SO 4 2–指示4-PAH +在头对头(HH)流行,并导致HH-photodimer的形成。给出了这两种环丁烷衍生物的阴离子控制的立体选择性合成的详细信息。有趣的是,两种环丁烷化合物在酸催化的溶液中都会从rctt形式异构化为rctc形式。