title: A diversity-oriented approach to spirocyclic and fused hydantoins via olefin metathesis.
abstract: 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.
authors.affiliation: Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal 741252, India.
authors.forename: Kalyan
authors.initials: K
authors.lastname: Dhara
authors.forename: Ganesh Chandra
authors.initials: GC
authors.lastname: Midya
authors.forename: Jyotirmayee
authors.initials: J
authors.lastname: Dash
mesh_terms: D000475:Alkenes / Q000138:chemical synthesis* / Q000737:chemistry*; D002384:Catalysis; D003500:Cyclization; D006827:Hydantoins / Q000138:chemical synthesis* / Q000737:chemistry*; D048288:Imidazolines / Q000138:chemical synthesis* / Q000737:chemistry*; D013141:Spiro Compounds / Q000138:chemical synthesis* / Q000737:chemistry*
chemical_list: D000475:Alkenes; D006827:Hydantoins; D048288:Imidazolines; D013141:Spiro Compounds