Highly Efficient Preparation of Selectively Isotope Cluster-Labeled Long Chain Fatty Acids via Two Consecutive C<sub>sp<sup>3</sup></sub>–C<sub>sp<sup>3</sup></sub> Cross-Coupling Reactions
作者:Sébastien Lethu、Shigeru Matsuoka、Michio Murata
DOI:10.1021/ol4036159
日期:2014.2.7
An efficient synthesis involving two copper-catalyzed alkyl–alkyl coupling reactions has been designed to easily access doubly isotope-labeled fatty acids. Such NMR- and IR-active compounds were obtained in excellent overall yields and will be further used for determining the conformation of an alkyl chain of lipidic biomolecules upon interaction with proteins.
Origin of the <i>E</i>/<i>Z</i> Selectivity in the Synthesis of Tetrasubstituted Olefins by Wittig Reaction of α-Fluorophosphonium Ylides: An Explanation for the Low Stereoselectivity Observed in Reactions of α-Alkoxy Aldehydes
作者:Dominique Depré、Wim A. A. Vermeulen、Yolande Lang、Jean Dubois、Jan Vandevivere、Jeremy Vandermeersch、Longchuan Huang、Raphaël Robiette
DOI:10.1021/acs.orglett.7b00344
日期:2017.3.17
96/4) by Wittig reactionbetween α-heterosubstituted ketones and α-fluorophosphonium ylides. A detailed study of factors that control stereoselectivity in these reactions shows that stereoselectivity is the result of stabilizing CH···F and N···C═O interactions in the addition TS leading to the E isomer. This analysis provides a rationale for the observed decrease in selectivity for reactions of stabilized
Total Synthesis of Ovafolinins A and B: Unique Polycyclic Benzoxepin Lignans through a Cascade Cyclization
作者:Samuel J. Davidson、David Barker
DOI:10.1002/anie.201705575
日期:2017.8.1
Ovafolinins A and B, isolated from Lyonia ovalifolia var. elliptica, are lignans that contain a unique bridged structure containing a penta‐ and tetracyclic benzoxepin and an aryl tetralin. We report the first total synthesis of these natural products in which an acyl‐Claisen rearrangement was initially utilized to construct the lignan backbone with correct relative stereochemistry. Judicious use of