The first enantioselective synthesis of (−)-conolutinine was achieved in 10 steps. The synthesis featured a catalytic asymmetric bromocyclization of tryptamine to forge the tricycle intermediate. Hydration of an alkene catalyzed by Co(acac)₂ was also employed as a key step to diastereoselectively introduce the tertiary alcohol moiety. The absolute configuration of (−)-conolutinine was established to be (2S,5aS,8aS,13aR) based on this asymmetric total synthesis.

 

 

Total Synthesis of (−)-Conolutinine

Xiangyang Feng^†‡, Guangde Jiang^‡, Zilei Xia^‡, Jiadong Hu^†‡, Xiaolong Wan^§, Jin-Ming Gao^†, Yisheng Lai^*‡, and Weiqing Xie^*†§

^† Shaanxi Key Laboratory of Natural Products & Chemical Biology, College of Science, Northwest A&F University, 22 Xinong Road, Yangling 712100, Shaanxi, China

^‡ State Key Laboratory of Natural Medicines, Jiangsu Key Laboratory of Drug Discovery for Metabolic Diseases, Center of Drug Discovery, China Pharmaceutical University, 24 Tongjiaxiang, Nanjing 210009, China

^§ State Key Laboratory of Bioorganic & Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 345 Lingling Lu, Shanghai 200032, China

Org. Lett., Article ASAP

DOI: 10.1021/acs.orglett.5b02046

http://pubs.acs.org/doi/abs/10.1021/acs.orglett.5b02046

 http://pubs.acs.org/doi/suppl/10.1021/acs.orglett.5b02046/suppl_file/ol5b02046_si_001.pdf

*E-mail: yslai@cpu.edu.cn., *E-mail: xiewq@nwafu.edu.cn.

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Acyl nitroso Diels–Alder (ANDA) reaction of sorbate esters and sorbic alcohol derivatives

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We present a study of the acyl nitroso Diels–Alder (ANDA) reaction of sorbate esters and sorbic alcohol derivatives, using alkoxycarbonyl nitroso dienophiles. An optimisation of the reaction conditions for ethyl sorbate is first presented, and the product is used in an efficient synthesis of 5-methylornithine. Structure–reactivity trends in sorbic alcohol (E,E-2,4-hexadien-1-ol) and its acylated analogues are then discussed. We present single-crystal X-ray structural proof for key adducts in both series and present in detail a novel HMBC/HSQC (¹H–¹⁵N) criterion for ready distinction of regioisomers arising from such ANDA reactions.

1H–15N long-range HSQC NMR of natural 15N abundance 10e (aryl hydrogens

The acyl nitroso Diels–Alder (ANDA) reaction of sorbate derivatives: an X-ray and ¹⁵N NMR study with an application to amino-acid synthesis

Lee Bollans,^a   John Bacsa,^a   Jonathan A. Iggo,^a   Gareth A. Morris^b and   Andrew V. Stachulski*^a  

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*Corresponding authors

^aRobert Robinson Laboratories, Department of Chemistry, University of Liverpool, Liverpool, UK
E-mail: stachuls@liv.ac.uk
Fax: 44 (0) 151 794 3588
Tel: 44 (0) 151 794 3542

^bSchool of Chemistry, University of Manchester, Oxford Rd., Manchester, UK

Org. Biomol. Chem., 2009,7, 4531-4538

http://pubs.rsc.org/en/content/articlelanding/2009/ob/b912963d#!divAbstract
DOI: 10.1039/B912963D                                                                                                                                                                                                                                                                                          ///////////

Ethyl sorbate

  Ethyl sorbate         .               1H NMR PREDICT 13C NMR PREDICT  

   

Automated VerifyIt Proton Assignments:

Automated VerifyIt Carbon Assignments:

 

Spectral Data Additional Data Download Type: 13C Atom No. ⇓ Mult.(coupling const.) Meas. Shift 1 D 118.6650 2 S 166.4830 3 D 144.2530 4 D 129.4060 5 T 59.4738 6 D 138.4450 7 Q 13.7465 8 Q 17.9926

COSY PREDICT

 
HMBC

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30(S)-hydroxybullatacin

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Total synthesis of 30(S)-hydroxybullatacin

In 2003, Marshall’s group disclosed a modular synthetic approach to the adjacent bis-THF rings (Scheme 46) [108]. This approach featured highly selective additions of chiral R-oxygenated allylic stannane and indium reagents such as B¹ and D¹ (M = SnBu₃ or InBr₂) to an acylic core aldehyde precursor (A¹ then C¹) followed by core ring closure (E¹ → F¹) and ensuing Sonogashira coupling (F¹ + G¹ → H¹) to append the butenolide segment. This straightforward strategy permitted the efficient assembly of the acetogenin structure from four basic subunits. By interchanging these subunits a variety of natural acetogenins and their isomers should be accessible in relatively few steps. They extended the scope of their modular four-component synthesis of annonaceous acetogenins to 30(S)-hydroxybullatacin (335). The ¹H and ¹³C NMR spectra of the tetraol product 335 were in complete agreement with the reported spectra [109].

Reference 109

109.	Gu, Z.-M.; Zeng, L.; Schwedler, J. T.; Wood, K. V.; McLaughlin, J. L. Phytochemistry 1995, 40, 467–477. doi:10.1016/0031-9422(95)00308-T

Go to reference 109

A synthesis of the bistetrahydrofuran Annonaceous acetogenins 30(S)-hydroxybullatacin, uvarigrandin A, and 5(R)-uvarigrandin A through application of a previously disclosed four-component modular approach is described in which extended core segments are coupled to a C4- or C5-hydroxy butenolide terminus. The butenolide termini segments were prepared from (S)- or (R)-malic acid. Spectral properties of synthetic 30(S)-hydroxybullatacin and uvarigrandin A, as well as their Mosher ester derivatives, were in close agreement to the reported values for the natural substances. The synthetic 5(R)-uvarigrandin A is possibly identical to narumicin I, but subtle differences in the reported NMR spectra prevented an unambiguous assessment of this point.

 http://pubs.acs.org/doi/abs/10.1021/jo0266137?journalCode=joceah


 nmr seehttp://pubs.acs.org/doi/suppl/10.1021/jo0266137/suppl_file/jo0266137_s.pdf

Recent progress on the total synthesis of acetogenins from Annonaceae

Nianguang Li¹, Zhihao Shi², Yuping Tang³, Jianwei Chen¹ and Xiang Li¹

¹Department of Medicinal Chemistry, Nanjing University of Chinese Medicine, No. 138, Xianlindadao, Nanjing, Jiangsu 210046, P. R. China. Tel & Fax: +86-25-85811512
²Division of Organic Chemistry, China Pharmaceutical University, Nanjing, Jiangsu 211198, P. R. China
³Jiangsu Key Laboratory for TCM Formulae Research, Nanjing University of Chinese Medicine, Nanjing, Jiangsu 210046, P. R. China.

Corresponding author email     

Beilstein J. Org. Chem. 2008, 4, No. 48.

 http://www.beilstein-journals.org/bjoc/single/articleFullText.htm?publicId=1860-5397-4-48

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1,2-epoxy-4-iodobutane

1,2-epoxy-4-iodobutane




C₄H₇OI
NMR Solvent: CDCl₃





 

Automated VerifyIt Proton Assignments:

Automated VerifyIt Carbon Assignments:

Spectral Data

Additional Data

Download

Type: 13C		Atom No. ⇓ Mult.(coupling const.) Meas. Shift 1 D 52.35960 2 T 0.21127 3 T 36.34340 4 T 46.88940

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