Stereoselective total synthesis of (+)-radicamine B via anti, syn, syn-oxazine. Issue 4 (15th March 2016) - Kim, Jin-Seok
Graphical abstract: Abstract: The stereoselective total synthesis of (+)-radicamine B was achieved using commercially availabled -4-hydroxy-phenylglycine via chiral 1, 3-oxazine, which has been applied to synthesis of amino polyols such as DAB-1, d -fagomine, and phytosphingosines. The key steps in this strategy were the palladium(0)-catalyzed stereoselective intramolecular oxazine formation, an extension of the chirality of anti, syn -oxazine with Lewis acid and vinylmagnesium bromide, and pyrrolidine ring formation via hydrogenation reaction. The chiral extension is also applicable to other chiral 1, 3-oxazine derived fromd -4-hydroxy-phenylglycine. Abstract : ( R )- N -(2-(Methoxy-(methyl)amino)-1-(4-nnethoxyphenyl)-2-oxoethyl)benzannide: C18 H20 N2 O4 [ α ]D 25 = −115.3 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine Absolute configuration: ( R ) Abstract : ( R, E )- N -(5-Chloro-1-(4-methoxyphenyl)-2-oxopent-3-enyl)benzamide: C19 H18 CINO3 [ α ]D 25 = −191.7 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine Absolute configuration: ( R ) Abstract : N -((1 R, 2 S, E )-5-Chloro-2-hydroxy-1-(4-methoxyphenyl)pent-3-enyl)benzamide: C19 H2 OCINO3 [ α ]D 25 = −45.7 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 1-( R ), 2-( S ) Abstract : N -((1 R, 2 S, E)-2-( tert -Butyldimethylsilyloxy)-5-chloro-1-(4-methoxyphenyl)pent-3-enyl)benzamide: C25 H3 4CINO3 Si [ α ]D 25 = −46.9 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 1-( R ), 2-( S ) Abstract : (4 R, 5 R, 6 R )-5-( tert -Butyldimethylsilyloxy)-4-(4-methoxyphenyl)-2-phenyl-6-vinyl-5, 6-dihydro-4 H, 3-oxazine: C25 H33 NO3 Si [ α ]D 25 = −8.0 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 4-( R ), 5-( R ), 6-( R ) Abstract : ( S )-(4 R, 5 R, 6 R )-5-( tert -Butyldimethylsilyloxy)-4-(4-methoxyphenyl)-2-phenyl-5, 6-dihydro-4 H -1, 3-oxazin-6-yl)prop-2-en-1-ol: C26 H35 NO4 Si [ α ]D 25 = +5.1 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 1-( S )-1-(4 R, 5 R, 6 R ) Abstract : ( R )-1-((4 R, 5 R, 6 R )-5-( tert -Butyldimethylsilyloxy)-4-(4-methoxyphenyl)-2-phenyl-5, 6-dihydro-4 H -1, 3-oxazin-6-yl)prop-2-en-1-ol: C26 H35 NO4 Si [ α ]D 25 = +30.3 ( c 0.4, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 1-( S )-1-(4 R, 5 R, 6 R ) Abstract : ( S )-1-((4 R, 5 R, 6 S )-5-( tert -Butyldimethylsilyloxy)-4-(4-methoxyphenyl)-2-phenyl-5, 6-dihydro-4 H -1, 3-oxazin-6-yl)-2-hydroxyethyl methanesulfonate: C26 H37 NO7 SSi [ α ]D 25 = +28.5 ( c 0.3, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 1-(S)-1-(4 R, 5 R, 6 R ) Abstract : (2 R, 3 R, 4 R, 5 R )-4-( tert -Butyldimethylsilyloxy)-2-(hydroxymethyl)-5-(4-methoxyphenyl)pyrrolidin-3-ol: C18 H31 NO4 Si [ α ]D 25 = +7.6 ( c 0.1, CHCl3 ) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 2-( R )-3-( R )-4-( R )-5-( R ) Abstract : (2 R, 3 R, 4 R, 5 R )-4-(Hydroxy)-2-(hydroxymethyl)-5-(4-hydroxyphenyl)pyrrolidin-3-ol: C11 H15 NO4 [ α ]D 25 = +42.8 ( c 0.04, MeOH) Source of chirality:d -4-hydroxyphenyl glycine and asymmetric synthesis Absolute configuration: 2-( R )-3-( R )-4-( R )-5-( R )