title: Synthesis of isochromene-type scaffolds via single-flask Diels-Alder-[4 + 2]-annulation sequence of a silyl-substituted diene with menadione.
abstract: A sequential Diels-Alder reaction/silicon-directed [4 + 2]-annulation was developed to assemble hydroisochromene-type ring systems from menadione 2. In the first step, a Diels-Alder of the 1-silyl-substituted butadiene 1 with 2 furnished an intermediate cyclic allylsilane. Subsequently, TMSOTf promoted a [4 + 2]-annulation through trapping of an oxonium, generated by condensation between an aldehyde and the TBS protected alcohol resulted in the formation of a cis-fused hydroisochromene 13.
authors.affiliation: Department of Chemistry and Center for Chemical Methodology and Library Development, Metcalf Center for Science and Engineering, Boston University , 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States.
authors.forename: Jihoon
authors.initials: J
authors.lastname: Lee
authors.forename: James S
authors.initials: JS
authors.lastname: Panek
mesh_terms: D000447:Aldehydes / Q000737:chemistry; D000475:Alkenes / Q000737:chemistry*; D001578:Benzopyrans / Q000138:chemical synthesis* / Q000737:chemistry; D002070:Butadienes / Q000737:chemistry; D061565:Cycloaddition Reaction; D015394:Molecular Structure; D011090:Polyenes / Q000737:chemistry; D012821:Silanes / Q000737:chemistry*; D013237:Stereoisomerism; D024483:Vitamin K 3 / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000447:Aldehydes; D000475:Alkenes; D001578:Benzopyrans; D002070:Butadienes; D011090:Polyenes; D012821:Silanes; C511847:allylsilane; D024483:Vitamin K 3; C013658:propylene