title: Gold-Catalyzed Stereoselective Synthesis of Bicyclic Lactams and Ketones from N-Tosylynamidomethyl-Tethered Cyclohexenes.
abstract: Six-membered ring 3-enynamides underwent cycloisomerization in the presence of a catalytic amount of a gold(I) complex delivering mainly 4-azatricyclo[4.3.1.03,10]dec-2-ene derivatives and dibenz[cd,f]indole derivatives as the minor products under mild reaction conditions. Upon exposure to air, most aryl-substituted azatricycles led to bicyclic γ-lactams, while the ortho-tolyl- or alkyl-substituted azatricycles provided the corresponding bicyclic γ-lactams after oxidation with osmium tetraoxide and N-methylmorpholine-N-oxide. Under acidic conditions, the ortho-tolyl- or alkyl-substituted azatricycles were further transformed into 5-N-tosylaminomethyl-tethered bicyclo[4.2.0]octan-7-ones. The gold(I)-catalyzed tandem cycloisomerization/oxidation reaction also provided a new route for the synthesis of bridged bicyclic δ-lactams from six-membered ring 4-enynamides. The mild reaction conditions allowed the synthesis of a range of bicyclic γ- and δ-lactams and N-tosylaminomethyl-tethered bicyclo[4.2.0]octan-7-ones with high diastereoselectivities.
authors.affiliation: Department of Chemistry, National Taiwan Normal University , 88 Ding-Jou Road, Section 4, Taipei 11677, Taiwan, Republic of China.
authors.forename: Chang-Zhi
authors.initials: CZ
authors.lastname: Zhong
authors.affiliation: Department of Chemistry, National Taiwan Normal University , 88 Ding-Jou Road, Section 4, Taipei 11677, Taiwan, Republic of China.
authors.forename: Po-Ting
authors.initials: PT
authors.lastname: Tung
authors.affiliation: Department of Chemistry, National Taiwan Normal University , 88 Ding-Jou Road, Section 4, Taipei 11677, Taiwan, Republic of China.
authors.forename: Tsung-Han
authors.initials: TH
authors.lastname: Chao
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.identifier: 0000-0003-2963-5707
authors.initials: MP
authors.lastname: Yeh