摘要：A novel C33 botryococcane in a sedimentary sample from the Maoming Basin in China was found to have a methyl group positioned β to the quaternary carbon C-10 in its structure based on IR, MS and NMR analyses and Lindeman-Adams modelling. This structure is inconsistent with the prediction from the currently accepted botryococcene biosynthetic pathway and different from the skeleton for the C33 botryococcanes suggested in the literature. A C33 botryococcan-24-one with the same carbon skeleton as the C33 botryococcane was also found to co-occur in the sediment sample. The location of the carbonyl group at C-24 is different from that of a previously reported botryococcenone from an Australian collection of race B of Botryococcus braunii where it is positioned at C-15. We propose a biogeochemical pathway to explain the occurrence of this unique skeleton in the Maoming Basin sediment. The biochemical component of the pathway involves electrophilic or nucleophilic attack between two farnesyl diphosphates (FPPs) leading to direct or indirect formation of a C30 botryococcene via a cyclobutane ring intermediate (1′-2-3-2′ cyclisation). A Retro-Prins reaction and subsequent methylation gives rise to C29 and C33 botryococcenes in sequence. The geochemical component involves first in-water-column (photo)-oxidation of the alkene to a C33 botryococcanone and subsequent reduction (hydrogenation) to stabilize the ketone as an alkane.
© 2018 Elsevier Ltd

ISSN号：0146-6380

卷、期、页：卷124：103-111

发表日期：2018-10-01

影响因子：3.081000

期刊分区（SCI为中科院分区）：二区

收录情况：SCI（科学引文索引印刷版）,ESI（基本科学指标数据库）,EI（工程索引）,SCIE（科学引文索引网络版）

发表期刊名称：Organic Geochemistry

参与作者：廖晶,卢鸿,冯乔,周玉平,彭平安,盛国英

第一作者：史权

论文类型：期刊论文

论文概要：廖晶,卢鸿,冯乔,周玉平,史权,彭平安,盛国英，Identification of a novel C33 botryococcane and C33 botryococcanone in the Maoming Basin, China，Organic Geochemistry，2018，卷124：103-111

论文题目：Identification of a novel C33 botryococcane and C33 botryococcanone in the Maoming Basin, China