55166-20-6Relevant academic research and scientific papers
Isomerization-Asymmetric Hydrogenation Sequence Converting Racemic β-Ylidenecycloalkanols into Stereocontrolled β-Substituted Cycloalkanols Using a Ru Catalytic System with Dual Roles
Arai, Noriyoshi,Okabe, Yuki,Ohkuma, Takeshi
, p. 5540 - 5547 (2019)
Racemic β-ylidenecycloalkanols were transformed into the cis-β-substituted cycloalkanols with high enantio- and diastereoselectivities through an isomerization-asymmetric hydrogenation sequence with the (4,4′-bi-1,3-benzodioxole)-5,5′-diylbis[di(3,5-xylyl)phosphine (DM-Segphos)/2-dimethylamino-1-phenylethylamine (DMAPEN)-ruthenium(II) catalyst; such transformation hardly proceeded by single-step asymmetric hydrogenation. The reaction was usually carried out with a substrate-to-catalyst molar ratio of 500 under 4 to 10 atm of H2 to afford the products in cis/trans ratio up to 99:1 and 98% ee. Mechanistic experiments suggested that this catalytic system reversibly formed two reactive species, types (I) and (II), through a ruthenacyclic amide intermediate. The amide complex and allylic alcohol reacted to afford the allylic alkoxide complex with partial or full removal of diamine (type (I)), and this type (I) complex catalyzed isomerization of the allylic alcohols into the racemic α-substituted ketones. The RuH2 complex with chelation of diamine (type (II)) formed by reaction of the amide complex and hydrogen promoted asymmetric hydrogenation of racemic α-substituted ketone into the stereocontrolled β-substituted cycloalkanols through dynamic kinetic resolution. (Figure presented.).
Umpolung Strategy for Arene C?H Etherification Leading to Functionalized Chromanes Enabled by I(III) N-Ligated Hypervalent Iodine Reagents
Mikhael, Myriam,Guo, Wentao,Tantillo, Dean J.,Wengryniuk, Sarah E.
supporting information, p. 4867 - 4875 (2021/09/14)
The direct formation of aryl C?O bonds via the intramolecular dehydrogenative coupling of a C?H bond and a pendant alcohol represents a powerful synthetic transformation. Herein, we report a method for intramolecular arene C?H etherification via an umpoled alcohol cyclization mediated by an I(III) N-HVI reagent. This approach provides access to functionalized chromane scaffolds from primary, secondary and tertiary alcohols via a cascade cyclization-iodonium salt formation, the latter providing a versatile functional handle for downstream derivatization. Computational studies support initial formation of an umpoled O-intermediate via I(III) ligand exchange, followed by competitive direct and spirocyclization/1,2-shift pathways. (Figure presented.).
Synthesis of certain unsubstituted, 9-exo-(dialkylaminomethyl)-, and 9- endo-(aralkyl)-tricyclo [5.2.1.02,6 decane-8-ketoxime esters and ethers with local anesthetic and analgesic activities
Aboul-Enein M, Nabil,El-Azzouny, Aida,Abdallah, Nevine A.,Maklad, Yousreya A.,Saleh, Ola A.,Ebeid
, p. 197 - 208 (2007/10/03)
The synthesis of series of unsubstituted, 9-exo-(dialkylaminomethyl)-, and 9-endo-(aralkyl)tricyclo [5.2.1.0(2,6)] decane-8-ketoximes esters and ethers 3a-j, 4a-d, 7a-j and 13a-d from the oxime synthons 2, 6a-e, 12a and 12b, respectively, is described. Al
MECHANISTIC AND STEREOCHEMICAL ASPECTS OF THE 1,2-3,4 HYDRIDE REDUCTION OF ENONES
Gammill, Ronald B.,Nash, Sharon A.,Bell, Larry T.,Watt, William,Mizsak, Stephen A.,et al.
, p. 5303 - 5306 (2007/10/02)
A unique mode of metal hydride reduction of unsaturated ketones is described which proceeds with a high degree of regio- and stereocontrol.
