Conformationally Constrained Dipeptide Surrogates with Aromatic Side-Chains: Synthesis of 4-Aryl Indolizidin-9-one Amino Acids by Conjugate Addition to a Common α,ω-Diaminoazelate Enone Intermediate
作者:Jérôme Cluzeau、William D. Lubell
DOI:10.1021/jo0355855
日期:2004.3.1
Four methyl 9-oxo-8-(N-(Boc)-amino)-4-phenyl-1-azabicyclo[4.3.0]nonane carboxylates (11, 4-Ph-I9aa-OMe) were synthesized from (2S,8S,5E)-di-tert-butyl-4-oxo-5-ene-2,8-bis[N-(PhF)amino]azelate [(5E)-7, PhF = 9-(9-phenylfluorenyl)] via a seven-step process featuring a conjugate addition/reductive amination/lactam cyclization sequence. Various nucleophiles were used in the conjugate addition reactions
四个甲基-9-氧代-8-(ñ - (BOC) -氨基)-4-苯基-1-氮杂双环[4.3.0]壬烷羧酸(11,4-PH-I 9 AA-OME)从(2合成S,8 S,5 E)-二叔丁基-4-氧代-5-烯-2,8-双[ N-(PhF)氨基]壬二酸酯[(5 E)-7,PhF = 9-( 9-苯基芴基)]通过共轭加成/还原胺化/内酰胺环化序列为特征的七步过程。烯酮(5 E)-7的共轭加成反应中使用了各种亲核试剂作为制备具有不同取代基的α,ω-二氨基壬二酸酯的一般途径,尽管非对映选择性低,但芳基格氏试剂(9/1至15/1 drs)除外。通过色谱法和非对映选择性沉淀分离6-苯基壬二酸酯(6 S)-8d和(6 R)-8d,并独立地转化成4-Ph-1 I 9 aa-OMe。由(6 S)-8d选择性地以51%的产率制备(2 S,4 R,6 R,8 S)-4-Ph-I 9 aa-OMe 11。(6还原胺化- [R