Novel organomagnesium reagents in synthesis. Catalytic cyclomagnesiation of allenes in the synthesis of N-, O-, and Si-substituted 1Z,5Z-dienes
作者:Vladimir A. D'yakonov、Aleksey A. Makarov、Elina Kh. Makarova、Usein M. Dzhemilev
DOI:10.1016/j.tet.2013.06.106
日期:2013.9
An efficient method for the synthesis of valuable N-, O-, and Si-containing 1Z,5Z-diene compounds was developed. The method comprises Cp2TiCl2-catalyzed homo- and cross-cyclomagnesiation of 1,2-dienes by Grignard reagents (RMgR′) to give 2,5-dialkylidenemagnesacyclopentanes in up to 96% yield. This approach was successfully used in the synthesis of 5Z,9Z-dienoic acids, precursors of acetogenins and
Highly Regio- and Stereoselective Synthesis of Alkylidenecyclopropanes via Ru(II)-Pheox Catalyzed Asymmetric Inter- and Intramolecular Cyclopropanation of Allenes
An efficient protocol for the synthesis of optically active alkylidenecyclopropanes (ACPs) via the Ru(II)-Pheox catalyzed asymmetric cyclopropanation of allenes has been established. This catalytic system proceeded with high regioselectivity to give the ACP products in high yield with high diastereoselectivity (up to 99/1) and enantioselectivity (up to 99% ee).
The facile synthesis of the 5Z,9Z-dienoic acids and their topoisomerase I inhibitory activity
作者:Vladimir A. D'yakonov、Aleksey A. Makarov、Lilya U. Dzhemileva、Elina Kh. Makarova、Elza K. Khusnutdinova、Usein M. Dzhemilev
DOI:10.1039/c3cc44926b
日期:——
original, effective approach to the synthesis of natural and synthetic 5Z,9Z-dienoic acids in high yields (61-67%) and with high selectivity (>98%) was developed. The approach is based on the use of the new intermolecular catalytic cross cyclomagnesiation of terminal aliphatic and oxygenated 1,2-dienes upon treatment with Grignardreagents in the presence of the Cp2TiCl2 catalyst. High activity of (5Z
Enantioselective and Regiodivergent Addition of Purines to Terminal Allenes: Synthesis of Abacavir
作者:Niels Thieme、Bernhard Breit
DOI:10.1002/anie.201610876
日期:2017.2
The rhodium‐catalyzed atom‐economic asymmetric N‐selective intermolecular addition of purine derivatives to terminalallenes is reported. Branched allylic purines were obtained in high yields, regioselectivity and outstanding enantioselectivity utilizing a Rh/Josiphos catalyst. Conversely, linear selective allylation of purines could be realized in good to excellent regio‐ and E/Z‐selectivity with
Highly Regio- and Stereoselective Palladium(0)-Catalyzed Addition of Organoboronic Acids with 1,2-Allenic Sulfones, Sulfoxides, or Alkyl- or Aryl-Substituted Allenes in the Presence of Acetic Acid: An Efficient Synthesis of <i>E</i>-Alkenes
作者:Shengming Ma、Hao Guo
DOI:10.1055/s-2007-983822
日期:2007.9
reaction conditions were established to enable the palladium(0)-catalyzed addition of organoboronicacids with 1,2-allenic sulfones, sulfoxides, or alkyl- or aryl-substituted allenes in the presence of acetic acid. This reaction provides a new way for the stereoselective synthesis of tri- or tetrasubstituted E-alkenes. With arylboronic acids, the reactions of 1,2-allenic sulfones, sulfoxides, and alkyl-substituted