Tandem Ring-Closing/Cross-Metathesis Approach for the Synthesis of Synargentolide B and Its Stereoisomers
作者:Gowravaram Sabitha、Kontham Shankaraiah、Jhillu S. Yadav
DOI:10.1002/ejoc.201300434
日期:2013.8
stereoisomers have been accomplished from L-(+)- and D-(–)-diethyl tartrates, D-ribose, and D-mannitol as chiral pool starting materials. The key step was a tandem ring-closing/cross-metathesis reaction in which lactone formation and fragment coupling were accomplished in one pot. The spectroscopic data of synthetic product 2c were in agreement with those reported for the natural product. Synargentolide
Diisopropyl tartrate modified (E)-γ-[(cyclohexyloxy)dimethylsilyl]- and (E)-γ-(dimethylphenylsilyl)allylboronates: Chiral Reagents for the Enantio- and Diastereoselective synthesis of anti 1,2-diols and 2-butene-1,4-diols via the formal α- and γ-hydroxyallylation of aldehydes
作者:William R. Roush、Paul T. Grover
DOI:10.1016/s0040-4020(01)88869-4
日期:1992.1
Enantioselective synthesis of 4-substituted (E)-2-butene-1,4-diols and anti 1,2-diols are described. Highly diastereoselective reactions of aldehydes and the chiral PhMe2Si- and (C6H11O)Me2Si- substituted allylboronates 25 and 26 provide anti homoallylic 29 and 50, respectively. Epoxidation of 29 with dimethyl dioxirane followed by acid catalyzed Petersen rearrangement of the intermediate epoxysilanols
描述了4-取代的(E)-2-丁烯-1,4-二醇和抗1,2-二醇的对映选择性合成。醛与手性PhMe 2 Si-和(C 6 H 11 O)Me 2 Si-取代的烯丙基硼酸酯25和26的高度非对映选择性反应分别提供反均聚物29和50。29用二甲基二环氧乙烷环氧化,然后经酸催化的中间体环氧硅烷醇进行Petersen重排,可得到具有优异对映选择性(81-87%ee)的1,4-丁二醇27。Tamao氧化50提供抗二醇22(ee的64–72%)。这些程序尤其在与一系列氧化的手性醛进行双不对称反应时获得了优异的结果(图1和2)。这些方法有望用于非环状前体糖的非对映选择性合成中。
Horseradish Peroxidase-Catalyzed Enantioselective Reduction of Racemic Hydroperoxy Homoallylic Alcohols: A Novel Enzymatic Method for the Preparation of Optically Active, Unsaturated Diols and Hydroperoxy Alcohols
作者:Waldemar Adam、Michael Lazarus、Ute Hoch、Marion N. Korb、Chantu R. Saha-Möller、Peter Schreier
DOI:10.1021/jo980028h
日期:1998.9.1
The kinetic resolution of chiral diastereomeric hydroperoxy homoallylic alcohols 1 by horseradish peroxidase-catalyzed asymmetricreduction affords the opticallyactive (R,R) or (R,S) allylic diols 2 and (S,S) or (S,R) hydroperoxy homoallylic alcohols 1 in high enantiomeric excess (up to 99%).
The Ti-catalyzed epoxidation of opticallyactive (S,S)-hydroperoxy homoallylic alcohols 2 affords the epoxy diol (S,R,S)-4 in high diastereoselectivity (d.r. up to 95:5), while the opticallyactive hydroxy homoallylic alcohols (R,R)-3 are epoxidized by the β-hydroperoxy alcohol 5 under titanium catalysis to the corresponding epoxy (R,S,R)-diol 4 in a diastereomeric ratio up to > 99:1. This high diastereoselectivity
A convenient approach to total synthesis of synargentolide-B from l-ascorbic acid and d-ribose
作者:Saidulu Konda、K. Bhaskar、Lingaiah Nagarapu、Dattatray M. Akkewar
DOI:10.1016/j.tetlet.2014.03.133
日期:2014.5
A convenient and practical approach for the totalsynthesis of naturally occurring lactone synargentolide-B has been accomplished in 14 steps from the commercially available l-ascorbic acid and d-ribose involving Bestmann–Ohira reaction, zinc mediated allylation, ring closing-metathesis, and cross-metathesis reactions. The highlight of our strategy describes a one-pot reaction involving stereoselective