Novel versatile approach to an enantiopure 19-nor, des-C,D vitamin D3 derivative
作者:Hans Hilpert、Beat Wirz
DOI:10.1016/s0040-4020(00)01035-8
日期:2001.1
A short and efficient de novo route to the des-C,D vitamin D3 derivative 3 (Ro 65-2299), a potential antipsoriatic, has been developed. This route features an assembly strategy so far unexplored in vitamin D chemistry involving a modified Julia olefination of the A-ring ketone 30 and the 2-benzothiazolyl sulfone 60. Construction of the A-ring building block was accomplished by an efficient three-step
已经开发了一种短而有效的从头途径到潜在的抗银屑病的des -C,D维生素D 3衍生物3(Ro 65-2299)。这条路线的特点是迄今为止在维生素D化学中尚未探索的组装策略,该策略涉及对A环酮30和2-苯并噻唑基砜60进行改进的Julia烯化反应。A环结构单元的构建是通过高效的三步路线完成的,该路线从内消旋-1,3,5-环己烷三醇(26)开始,该过程通过相应三乙酸酯的高选择性酶促单水解反应来消除对称性。27,然后氧化酒精用图29所示的方法得到的纯手性二乙酰氧基酮30(ee = 99.5%),总产率为83%。此外,我们发现了5-乙酰氧基-2-环己烯酮(31)及其对映异构体32的有效和实用合成方法,这两种新方法都可用于天然产物的合成。
Regio- and stereoselective ring-opening of chiral 1,3-oxazolidin-2-one derivatives by organocopper reagents provides novel access to di-, tri- and tetra-substituted alkene dipeptide isosteresElectronic supplementary information (ESI) available: synthetic procedures and characterization for 4a,b, 5a,b, 7b, 8a,b, 9a,b, 10b, 11a,b, 12b,c, 13b, 14a,b, 15, 16a,b, 17a,b, 18, 19b, 20b. See http://www.rsc.org/suppdata/p1/b2/b203482d/
作者:Shinya Oishi、Ayumu Niida、Takae Kamano、Yoshihisa Miwa、Tooru Taga、Yoshihiko Odagaki、Nobuyuki Hamanaka、Mikio Yamamoto、Keiichi Ajito、Hirokazu Tamamura、Akira Otaka、Nobutaka Fujii
DOI:10.1039/b203482d
日期:2002.7.26
Organocopper-mediated alkylation of β-(
N-Boc-2-oxo-1,3-oxazolidin-5-yl)-α,β-enoates has been intensively investigated. Alkylation proceeded regio- and stereoselectively by
anti-
SN2′ ring-opening to provide a new route to the synthesis of
ψ[(
E)-CHCH]-,
ψ[(
E)-CMeCH]- and
ψ[(
E)-CMeCMe]- type alkene dipeptide isosteres from chiral amino acid derivatives. These resulting agents are potential mimetics of type II and type II′
β-turn substructure.
有机铜介导的β-(N-Boc-2-氧代-1,3-嗯唑烷-5-基)-α,β-烯酸酯的烷基化反应已被深入研究。通过反式-SN2'环开裂,烷基化反应在区域选择性和立体选择性上进行,为从手性氨基酸衍生物合成ψ[(E)-CHCH]-、ψ[(E)-CMeCH]-和ψ[(E)-CMeCMe]-型烯丙二肽类似物提供了一条新途径。这些合成的试剂是潜在的II型和II'型β-转角结构域模拟物。
Catalytic Enantioselective Construction of β-Quaternary Carbons via a Conjugate Addition of Cyanide to β,β-Disubstituted α,β-Unsaturated Carbonyl Compounds
作者:Yuta Tanaka、Motomu Kanai、Masakatsu Shibasaki
DOI:10.1021/ja1035286
日期:2010.7.7
The first general catalytic enantioselective conjugate addition of cyanide to beta,beta-disubstituted alpha,beta-unsaturated ketones and N-acylpyrroles was developed using a strontium catalyst derived from Sr(O(i)Pr)(2) and new chiral ligand 5. The reaction exhibited excellent enantioselectivity and a wide substrate scope using 0.5-10 mol % catalyst. 1,4-Adducts containing beta-quaternary carbons were
使用衍生自 Sr(O(i)Pr)(2) 和新手性配体 5 的锶催化剂,开发了第一个通用催化对映选择性共轭加成氰化物到 β、β-二取代 α、β-不饱和酮和 N-酰基吡咯。该反应表现出优异的对映选择性和广泛的底物范围,使用 0.5-10 mol% 的催化剂。含有 β-季碳的 1,4-加合物仅在 1,2-加合物上产生。锶催化剂的 ESI-MS 分析表明活性催化剂是三金属 Sr/5 = 3:5 配合物。独特的 1,4-选择性部分是由于锶络合物能够促进 1,2-加合物的逆氰化反应和高度对映选择性的共轭氰化反应。