Department of Chemistry and Biochemistry, Baylor University, One Bear Place 97348, Waco, TX, 76798, USA.
Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, 3086, Australia.
Chemistry. 2019 Jan 28;25(6):1581-1587. doi: 10.1002/chem.201805151. Epub 2018 Dec 27.
The reactions of a monomeric borole and a dimeric borole with 2,3-dimethyl-1,3-butadiene and 1,3-cyclohexadiene were investigated. The monomeric borole reacted at ambient temperature whereas heat was required to crack the dimer to form the monomer and induce reactivity. 2,3-Dimethyl-1,3-butadiene reacts to give diverse products resulting from a cycloaddition process with the B-C moiety of the boroles acting as a dienophile, followed by rearrangements to furnish bicyclic species. For 1,3-cyclohexadiene, a [4+2] process is observed in which 1,3-cyclohexadiene serves as the dienophile and the boroles as the diene partner. The experimental results are corroborated with mechanistic theoretical calculations that indicate boroles can serve as either a diene or dienophile in cycloaddition reactions with dienes.
研究了单体硼烷和二聚硼烷与 2,3-二甲基-1,3-丁二烯和 1,3-环己二烯的反应。单体硼烷在室温下反应，而二聚体需要加热裂解形成单体并引发反应。2,3-二甲基-1,3-丁二烯反应生成多种产物，这是硼烷的 B-C 部分作为亲二烯体的环加成过程的结果，随后发生重排以提供双环物种。对于 1,3-环己二烯，观察到[4+2]过程，其中 1,3-环己二烯作为亲二烯体，硼烷作为二烯体伙伴。实验结果得到了机理理论计算的证实，表明硼烷在与二烯的环加成反应中可以作为二烯或亲二烯体。
