Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741252, India.
J Org Chem. 2012 Sep 21;77(18):8071-82. doi: 10.1021/jo301234r. Epub 2012 Sep 12.
An efficient and general method is reported to prepare a diverse series of 5,5-spirocyclic and 1,5-, 4,5-, and 3,4-fused bicyclic imidazolidinone derivatives based on selective alkylation and ring closing metathesis (RCM) by exploiting the four possible points of diversity in the hydantoin ring. Hydantoins containing trienes and tetraenes undergo selective RCM and cross metathesis to afford functionalized spirohydantoins. A tandem metathesis sequence involving ring closing-ring opening-ring closing and cross metathesis (RC-RO-RC-CM) occurred with a hydantoin triene to give a bicyclic hydantoin dimer in high yield. The fused bicylic dimer could participate in cross metathesis to produce a functionalized fused hydantoin derivative. The methodology establishes novel routes to unnatural amino acids, proline homologues, and cyclic vicinal diamines.
报道了一种高效、通用的方法，通过利用海因环上的四个可能的多样性点，选择性烷基化和闭环复分解（RCM）来制备一系列不同的 5,5-螺环和 1,5-、4,5-和 3,4-稠合双环咪唑烷酮衍生物。含三烯和四烯的海因可以进行选择性 RCM 和交叉复分解反应，得到功能化的螺海因。与海因三烯发生的串联复分解反应序列包括闭环-开环-闭环和交叉复分解（RC-RO-RC-CM），以高产率得到双环海因二聚体。稠合双环二聚体可以参与交叉复分解反应，生成功能化稠合海因衍生物。该方法为非天然氨基酸、脯氨酸类似物和环状顺式二胺的合成提供了新途径。
