| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1348282 | Tetrahedron: Asymmetry | 2007 | 9 Pages |
A highly stereoselective approach to 1,3,4,5- and 1,3,3′,4,5-polysubstituted 2-oxopiperazines is reported. The method is based on the synthetic elaboration of naturally occurring amino acids to obtain enantiomerically enriched C-5 substituted oxopiperazines, which are further functionalized at C-3 via enolate formation and reaction with electrophiles. Notably, the two nitrogens of the ring can be orthogonally protected.
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(S)-tert-Butyl-1-(benzylamino)-propan-2-yl-carbamateC15H24N2O2[α]D24=-1.8 (c 1.05, CHCl3)Source of chirality = l-alanineAbsolute configuration: (S)
(S)-tert-Butyl-1-(benzylamino)-3-methyl-butan-2-yl-carbamateC17H28N2O2[α]D24=+1.2 (c 0.94, CHCl3)Source of chirality = l-valineAbsolute configuration: (S)
(S)-tert-Butyl-1-(benzylamino)-3-[4-(benzyloxy)-phenyl]-propan-2-yl-carbamateC28H34N2O3[α]D24=-1.4 (c 1.09, CHCl3)Source of chirality = l-tyrosineAbsolute configuration: (S)
(S)-1-(Benzyl)-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC17H24N2O3[α]D24=+0.7 (c 0.81, CHCl3)Source of chirality = l-alanineAbsolute configuration: (S)
(S)-1-(Benzyl)-4-tert-butoxycarbonyl-5-isopropyl-2-oxopiperazineC19H28N2O3[α]D24=+0.9 (c 0.45, CHCl3)Source of chirality = l-valineAbsolute configuration: (S)
(S)-1-(Benzyl)-4-tert-butoxycarbonyl-5-[(4-benzyloxy)-benzyl-2-oxopiperazineC30H34N2O4[α]D24=-62.9 (c 1.00, CHCl3)Source of chirality = l-tyrosineAbsolute configuration: (S)
(3S,5S)-1-(Benzyl)-3-allyl-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC20H28N2O3[α]D24=+11.1 (c 1.26, CHCl3)Source of chirality = l-alanineAbsolute configuration: (3S,5S)
(3S,5S)-1-(Benzyl)-3-allyl-4-tert-butoxycarbonyl-5-isopropyl-2-oxopiperazineC22H32N2O3[α]D24=+1.0 (c 1.00, CHCl3)Source of chirality = l-valineAbsolute configuration: (3S,5S)
(3S,5S)-1-(Benzyl)-3-allyl-4-tert-butoxycarbonyl-5-4-[(benzyloxy)-benzyl]-2-oxopiperazineC33H38N2O4[α]D24=-31.8 (c 1.31, CHCl3)Source of chirality = l-tyrosineAbsolute configuration: (3S,5S)
(3S,5S)-1-(Benzyl)-3-methoxymethyl-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC19H28N2O4[α]D24=+14.4 (c 0.61, CHCl3)Source of chirality = l-alanineAbsolute configuration: (3S,5S)
(3S,5S)-1,3-Dibenzyl-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC24H30N2O3[α]D24=+15.1 (c 1.00, CHCl3)Source of chirality = l-alanineAbsolute configuration: (3S,5S)
(3S,5S)-1-Benzyl-3-(ethoxycarbonylmethyl)-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC21H30N2O5[α]D24=9.4 (c 0.93, CHCl3)Source of chirality = l-alanineAbsolute configuration: (3S,5S)
(S)-1-Benzyl-3,3′-diallyl-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC23H32N2O3[α]D24=-3.3 (c 0.25, CHCl3)Source of chirality = l-alanineAbsolute configuration: (S)
(3S,5S)-1-Benzyl-3-allyl-3′-benzyl-4-tert-butoxycarbonyl-5-methyl-2-oxopiperazineC27H342N2O3[α]D24=+0.4 (c 0.65, CHCl3)Source of chirality = l-alanineAbsolute configuration: (3S,5S)
