title: Catalytic Asymmetric Cascade Vinylogous Mukaiyama 1,6-Michael/Michael Addition of 2-Silyloxyfurans with Azoalkenes: Direct Approach to Fused Butyrolactones.
abstract: An unprecedented cascade vinylogous Mukaiyama 1,6-MA/MA of 2-silyloxyfurans and azoalkenes was realized with a Cu(II)/(t)Bu-Box complex. An array of fused butyrolactones containing multiple stereocenters was generally obtained in good yield (up to 90% yield) with exclusive diastereoselectivity (>20:1 dr) and excellent enantioselectivity (up to 99% ee). Carbon isotope effects measured by (13)C NMR revealed a stepwise mechanism for this annulation process.
authors.forename: Jun
authors.initials: J
authors.lastname: Li
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.forename: Yi-Kang
authors.initials: YK
authors.lastname: Xing
authors.forename: Guofu
authors.initials: G
authors.lastname: Qiu
authors.forename: Hai-Yan
authors.initials: HY
authors.lastname: Tao
authors.affiliation: §State Key Laboratory of Elemento-organic Chemistry, Nankai University, Tianjin 300071, China.
authors.forename: Chun-Jiang
authors.initials: CJ
authors.lastname: Wang
mesh_terms: D000475:Alkenes / Q000737:chemistry; D002247:Carbon Isotopes; D002384:Catalysis; D060326:Chemistry Techniques, Synthetic; D005663:Furans / Q000737:chemistry; D007783:Lactones / Q000138:chemical synthesis* / Q000737:chemistry; D009682:Magnetic Resonance Spectroscopy; D015394:Molecular Structure; D013237:Stereoisomerism
chemical_list: D000475:Alkenes; D002247:Carbon Isotopes; D005663:Furans; D007783:Lactones