title: Synthesis of function-oriented 2-phenyl-2H-chromene derivatives using L-pipecolinic acid and substituted guanidine organocatalysts.
abstract: Organocatalytic domino oxa-Michael/aldol reactions between salicylaldehyde with electron deficient olefins are presented. We screened guanidine, 1,1,3,3-tetramethylguanidine (TMG) and L-pipecolinic acid as organocatalysts for this transformation. 3-Substituted 2-phenyl-2H-chromene derivatives are synthesized with high yields and with poor enantioselectivity (5-17% ee) using L-pipecolinic acid while TMG works well with cinnamaldehyde without using co-catalyst. These 3-substituted-2-phenyl-2H-chromene derivatives are further derivatized to synthesize triazole and biotin-containing chromene derivatives, to facilitate purification of protein targets.
authors.affiliation: Department of Nuclear Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
authors.forename: Bhaskar C
authors.initials: BC
authors.lastname: Das
authors.forename: Seetaram
authors.initials: S
authors.lastname: Mohapatra
authors.forename: Philip D
authors.initials: PD
authors.lastname: Campbell
authors.forename: Sabita
authors.initials: S
authors.lastname: Nayak
authors.forename: Sakkarapalayam M
authors.initials: SM
authors.lastname: Mahalingam
authors.forename: Todd
authors.initials: T
authors.lastname: Evans