97732-60-0Relevant academic research and scientific papers
Stereoconvergent and -divergent synthesis of tetrasubstituted alkenes by nickel-catalyzed cross-couplings
Zell, Daniel,Kingston, Cian,Jermaks, Janis,Smith, Sleight R.,Seeger, Natalie,Wassmer, Jana,Sirois, Lauren E.,Han, Chong,Zhang, Haiming,Sigman, Matthew S.,Gosselin, Francis
, p. 19078 - 19090 (2021/11/22)
We report the development of a method to diastereoselectively access tetrasubstituted alkenes via nickel-catalyzed Suzuki-Miyaura cross-couplings of enol tosylates and boronic acid esters. Either diastereomeric product was selectively accessed from a mixture of enol tosylate starting material diastereomers in a convergent reaction by judicious choice of the ligand and reaction conditions. A similar protocol also enabled a divergent synthesis of each product isomer from diastereomerically pure enol tosylates. Notably, high-throughput optimization of the monophosphine ligands was guided by chemical space analysis of the kraken library to ensure a diverse selection of ligands was examined. Stereoelectronic analysis of the results provided insight into the requirements for reactive and selective ligands in this transformation. The synthetic utility of the optimized catalytic system was then probed in the stereoselective synthesis of various tetrasubstituted alkenes, with yields up to 94% and diastereomeric ratios up to 99:1 Z/E and 93:7 E/Z observed. Moreover, a detailed computational analysis and experimental mechanistic studies provided key insights into the nature of the underlying isomerization process impacting selectivity in the cross-coupling.
Stereoselective cross-coupling reaction of 1,1-diboryl-1-alkenes with electrophiles: A highly stereocontrolled approach to 1,1,2-triaryl-1-alkenes
Shimizu, Masaki,Nakamaki, Chihiro,Shimono, Katsuhiro,Schelper, Michael,Kurahashi, Takuya,Hiyama, Tamejiro
, p. 12506 - 12507 (2007/10/03)
Palladium-catalyzed cross-coupling reaction of 1,1-diboryl-1-alkenes with aryl and alkenyl iodides was found to proceed stereoselectively, giving rise to the corresponding mono-coupled product as a single diastereomer with E-configuration. Second coupling of the initial product with another aryl iodide affords diverse triarylalkenes in their stereochemically pure form. This highly stereoselective approach for triarylalkenes allows one to synthesize both diastereomers in one pot from 1,1-diboryl-1-alkenes. Copyright
Synthesis and receptor-binding affinity of fluorotamoxifen, a possible estrogen-receptor imaging agent
Shani,Gazit,Livshitz,Biran
, p. 1504 - 1511 (2007/10/02)
Aminotamoxifen was totally synthesized from p-nitrobenzoyl chloride via a Friedel-Crafts acylation. Then, by means of a Balz-Schiemann reaction, aminotamoxifen was converted into fluorotamoxifen. The triazene variation of this conversion, with a 25% yield, enables a rapid, one-step diazotization, incorporating a fluorine atom into the phenyl ring of the tamoxifen. This reaction may be useful for the preparation of low specific activity 18F-labeled tamoxifen, for distribution, and for estrogen-receptor studies. For these in vivo and in vitro studies, fluorotamoxifen was also synthesized from p-fluorobenzoyl chloride, and its chemical intermediates were compared with estradiol and hexestrol, for their receptor binding and competition, as well as for their uterotropic activity. It is demonstrated that tamoxifen and fluorotamoxifen are strong estradiol agonists and partial hexestrol agonists, while aminotamoxifen is a weak estradiol and hexestrol agonist.
