5-epi-Incensole: synthesis, X-ray crystal structure and absolute configuration by means of ECD and VCD studies in solution and solid state. Issue 17 (1st October 2016)

• Record Type: Journal Article
• Authors: Avula, Satya Kumar; Hussain, Hidayat; Csuk, René; Sommerwerk, Sven; Liebing, Phil; Górecki, Marcin; Pescitelli, Gennaro; Al-Rawahi, Ahmed; Ur Rehman, Najeeb; Green, Ivan R.; Al-Harrasi, Ahmed
• Is Part Of: Tetrahedron, asymmetry. Volume 27:Issue 17/18(2016)
• Page Start: 829
• Page End: 833
• Publication Date: 2016-10-01
• Subjects: Asymmetry (Chemistry) -- Periodicals; 547.005
• DOI: 10.1016/j.tetasy.2016.07.007
• Languages: English
• ISSNs: 0957-4166

Abstract

Graphical abstract: Abstract: Incensole1 and its acetate2, found in incense, demonstrate interesting biological activities. Incensole acetate2 was prepared on a large scale by employing the Paul and Jauch protocol from the crude extracts of Boswellia papyrifera Hochst. 5- epi -Incensole3, obtained as colorless crystals, was prepared from incensole acetate via three steps; deacetylation, oxidation and reduction. The structure of 5- epi -incensole3 was elucidated by means of spectroscopic data analysis, and the absolute configuration was established by single crystal X-ray analysis in combination with electronic and vibrational circular dichroism. In particular, the applicability of the solid-state ECD/TDDFT protocol to a compound with only two non-conjugated alkene chromophores was verified. Abstract : (+)-(1 S, 4 R, 5 R )-5- epi -Incensole: C20 H34 O2 Absolute configuration: (1 S, 4 R, 5 R ) (assigned by NMR, X-ray analysis, ECD, VCD, TDDFT) [ α ]D 25 = −11.8 ( c 0.06, CH2 Cl2 )