Bisabolyl-derived sesquiterpenes from tobacco 5-epi-aristolochene synthase-catalyzed cyclization of (2Z,6E)-farnesyl diphosphate

Faraldos, Juan A., O'Maille, Paul E., Dellas, Nikki, Noel, Joseph P. and Coates, Robert M. 2010. Bisabolyl-derived sesquiterpenes from tobacco 5-epi-aristolochene synthase-catalyzed cyclization of (2Z,6E)-farnesyl diphosphate. Journal of the American Chemical Society 132 (12) , pp. 4281-4289. 10.1021/ja909886q

Full text not available from this repository.

Abstract

We report the structures and stereochemistry of seven bisabolyl-derived sesquiterpenes arising from an unprecedented 1,6-cyclization (cisoid pathway) efficiently catalyzed by tobacco 5-epi-aristolochene synthase (TEAS). The use of (2Z,6E)-farnesyl diphosphate as an alternate substrate for recombinant TEAS resulted in a robust enzymatic cyclization to an array of products derived exclusively (≥99.5%) from the cisoid pathway, whereas these same products account for ca. 2.5% of the total hydrocarbons obtained using (2E,6E)-farnesyl diphosphate. Chromatographic fractionations of extracts from preparative incubations with the 2Z,6E substrate afforded, in addition to the acyclic allylic alcohols (2Z,6E)-farnesol (6.7%) and nerolidol (3.6%), five cyclic sesquiterpene hydrocarbons and two cyclic sesquiterpene alcohols: (+)-2-epi-prezizaene (44%), (−)-α-cedrene (21.5%), (R)-(−)-β-curcumene (15.5%), α-acoradiene (3.9%), 4-epi-α-acoradiene (1.3%), and equal amounts of α-bisabolol (1.8%) and epi-α-bisalolol (1.8%). The structures, stereochemistry, and enantiopurities were established by comprehensive spectroscopic analyses, optical rotations, chemical correlations with known sesquiterpenes, comparisons with literature data, and GC analyses. The major product, (+)-2-epi-prezizaene, is structurally related to the naturally occurring tricyclic alcohol, jinkohol (2-epi-prezizaan-7β-ol). Cisoid cyclization pathways are proposed by which all five sesquiterpene hydrocarbons are derived from a common (7R)-β-bisabolyl+/pyrophosphate− ion pair intermediate. The implications of the “cisoid” catalytic activity of TEAS are discussed.

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Chemistry
Subjects:	Q Science > QD Chemistry
Publisher:	American Chemical Society
ISSN:	0002-7863
Last Modified:	23 Mar 2017 03:41
URI:	https://orca.cardiff.ac.uk/id/eprint/35307

Citation Data

Cited 35 times in Scopus. View in Scopus. Powered By Scopus® Data

Actions (repository staff only)

Edit Item