title: Syntheses of 3,4-disubstituted pyrroles and furans via Lewis acid-promoted semipinacol rearrangement/alkyne-ketone metathesis reaction of (C)-2-N- or O-((3-arylpropargyl)methyl)-tethered 3,5,5-trimethyl-2,3-epoxycyclohexan-1-ones.
abstract: The synthesis of 2,3-disubstituted pyrroles via TMSOTf-assisted cyclization reaction of 3,5,5-trimethyl-2,3-epoxycyclohexan-1-ones incorporating a (3-arylpropargyltosylamino)methyl tether at the C-2 position is described. The reaction starts with an acid-promoted semipinacol rearrangement to give a ring contraction cyclopentanone moiety bearing an arylpropargylaminoacetyl side chain. A subsequent alkyne-ketone metathesis affords the pyrrole derivatives in good yields. The 3,4-disubstituted furan analogues can also be available from 3,5,5-trimethyl-2,3-epoxycyclohexan-1-ones with a tethered arylpropargyl methyl ether at the C-2 position and BF3·OEt2 under an atmosphere of oxygen.
authors.affiliation: Department of Chemistry, National Taiwan Normal University , 88 Ding-Jou Road, Section 4, Taipei 11677, Taiwan, Republic of China.
authors.forename: Ming-Chang P
authors.initials: MC
authors.lastname: Yeh
authors.forename: Ming-Nan
authors.initials: MN
authors.lastname: Lin
authors.forename: Ching-Hsien
authors.initials: CH
authors.lastname: Hsu
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Liang
mesh_terms: D000480:Alkynes / Q000737:chemistry*; D003512:Cyclohexanones / Q000737:chemistry*; D005663:Furans / Q000138:chemical synthesis* / Q000737:chemistry; D007659:Ketones / Q000737:chemistry*; D058116:Lewis Acids / Q000737:chemistry*; D015394:Molecular Structure; D011758:Pyrroles / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D000480:Alkynes; D003512:Cyclohexanones; D005663:Furans; D007659:Ketones; D058116:Lewis Acids; D011758:Pyrroles