Stereoselective Synthesis of the Butyrolactone and the Oxazoline/Furan Fragment of Leupyrrin A1
摘要:
Stereoselective syntheses of the Northern and the Southern fragments 2 and 3 of leupyrrin A(1) are reported. The convergent preparation of 2 is highlighted by a zirconocene-mediated one-pot cyclization-regioselective opening of an advanced diyne while the route to 3 involves a Krische allylation and a one-pot Sharpless dihydroxylation-cyclization. Comparison of the spectroscopic data with those reported for the natural product supports a relative stereochemical assignment within these heterocycles.
Stereoselective Synthesis of the Butyrolactone and the Oxazoline/Furan Fragment of Leupyrrin A1
摘要:
Stereoselective syntheses of the Northern and the Southern fragments 2 and 3 of leupyrrin A(1) are reported. The convergent preparation of 2 is highlighted by a zirconocene-mediated one-pot cyclization-regioselective opening of an advanced diyne while the route to 3 involves a Krische allylation and a one-pot Sharpless dihydroxylation-cyclization. Comparison of the spectroscopic data with those reported for the natural product supports a relative stereochemical assignment within these heterocycles.
[EN] TRANSITION METAL-CATALYZED IMIDATION OF ARENES<br/>[FR] IMIDATION D'ARÈNES CATALYSÉE PAR DES MÉTAUX DE TRANSITION
申请人:HARVARD COLLEGE
公开号:WO2015031725A1
公开(公告)日:2015-03-05
The present invention provides novel transition metal complexes (e.g., complexes of any one of Formulae (C1) to (C25)) that include an amine-N-oxide motif. The invention also provides methods of using these transition metal complexes in preparing N-aryl or N- heteroaryl sulfonimides (e.g., compounds of Formula (I)) and aryl or heteroaryl amines (e.g., compounds of Formula (II)). The inventive methods involve imidation of arenes and heteroarenes (e.g., compounds of Formula (A)) using an imidating agent (e.g., a compound of Formula (B), such as N-fluorobenzenesulfonimide (NFBS or NFSI)) in the presence of a single-electron reductant (e.g., an Ag(I) or Ru(II) salt).
The enantioselective synthesis of APTO and AETD: polyhydroxylated β-amino acid constituents of the microsclerodermin cyclic peptides
作者:Emily C. Shuter、Hung Duong、Craig A. Hutton、Malcolm D. McLeod
DOI:10.1039/b707891a
日期:——
The polyhydroxylated beta-amino acids (2S,3R,4S,5S,7E)-3-amino-8-phenyl-2,4,5-trihydroxyoct-7-enoic acid (APTO) and (2S,3R,4S,5S,7E,9E)-3-amino-10-(4-ethoxyphenyl)-2,4,5-trihydroxydeca-7,9-dienoic acid (AETD) are key components of the microsclerodermin family of anti-fungal cyclic peptides. They have been synthesised in protected form in twelve steps using a unified strategy, with the introduction
The oxytocinase subfamily of M1 zinc aminopeptidases comprises emerging drug targets, including the ER-resident aminopeptidases 1 and 2 (ERAP1 and ERAP2) and insulin-regulatedaminopeptidase (IRAP); however, reports on clinically relevant inhibitors are limited. Here we report a new synthetic approach of high diastereo- and regioselectivity for functionalization of the α-hydroxy-β-amino acid scaffold
M1 锌氨肽酶的催产素酶亚家族包括新兴的药物靶点,包括 ER 驻留氨肽酶 1 和 2(ERAP1 和 ERAP2)和胰岛素调节氨肽酶(IRAP);然而,关于临床相关抑制剂的报道有限。在这里,我们报告了一种新的合成方法,该方法具有高非对映选择性和区域选择性,可用于 bestatin 的 α-羟基-β-氨基酸支架的功能化。通过与微摩尔抑制剂复合的 ERAP1 的高分辨率 X 射线晶体结构研究了立体化学和抑制机制。通过探索 P1 侧链功能,我们获得了显着的效力和选择性,并且我们报告了一种具有细胞活性的低纳摩尔 IRAP 抑制剂,其选择性比同源酶高 120 倍以上。IRAP 与该抑制剂复合的 X 射线晶体学分析表明,与 GAMEN 环的相互作用是效力和选择性的一个未被认可的关键决定因素。总体而言,我们的结果表明,α-羟基-β-氨基酸衍生物可能构成这组氨肽酶的有用化学工具和药物先导物。
Pd-Catalyzed Aryl C–H Imidation with Arene as the Limiting Reagent
作者:Gregory B. Boursalian、Ming-Yu Ngai、Katarzyna N. Hojczyk、Tobias Ritter
DOI:10.1021/ja4064926
日期:2013.9.11
An amine-N-oxide-ligated palladium complex, in conjunction with a silver cocatalyst, catalyzes imidation of arenes by the reagent N-fluorobenzenesulfonimide. The reaction enables imidation of a variety of arenes at or below room temperature, requires no coordinating directing group on the substrate, and gives synthetically useful yields with only 1 equiv of arene. Mechanistic data implicate an unusual mechanism devoid of commonly invoked organometallic intermediates: oxidation of the Pd catalyst occurs as the turnover-limiting step, while C-H bond functionalization occurs subsequently at a high oxidation state of the catalyst.