130607-54-4Relevant academic research and scientific papers
Relay catalysis: Enantioselective synthesis of cyclic benzo-fused homoallylic alcohols by chiral bronsted acid-catalyzed allylboration/ring closing metathesis
Fustero, Santos,Rodriguez, Elsa,Lazaro, Ruben,Herrera, Lidia,Catalan, Silvia,Barrio, Pablo
supporting information, p. 1058 - 1064 (2013/05/21)
Six- and seven-membered benzo-fused cyclic homoallylic alcohols can be readily synthesized by a tandem chiral Bronsted acid-catalyzed allyl (crotyl)boration/ring closing metathesis sequence performed under orthogonal relay catalysis conditions. Excellent enantio- and diastereoselectivities are obtained in most of the cases. In addition, the parent crotylboration/RCM process is also described. The required substrates, ortho-vinylbenzaldehydes, are readily available in one step from commercially available starting materials. Both catalysts and reactants are also available from commercial suppliers. The reaction shows broad functional group compatibility and is also suitable for heteroaromatic substrates. Substitution at any position of the aromatic ring is tolerated; however, substitution at position 6 results in a substantial drop in enantioselectivity. Copyright
Solvent induced isomerization of 2-cyclohexen-1-ol to 3-cyclohexen-1-ol by a chiral lithium amide
Khan, Agha Zul-Qarnian,Arvidsson, Per I.,Ahlberg, Per
, p. 399 - 402 (2007/10/03)
Enantioselective deprotonation by lithium (S)-1-(2-pyrrolidinylmethyl)pyrrolidine 1 of cyclohexene oxide 2 on changing the solvent from tetrahydrofuran (THF) to cis-2,5-dimethyl-THF (cis-DMTHF) gives the homoallylic alcohol 3-cyclohexen-1-ol 4 up to 74% yield as isomerized product besides the 2-cyclohexen-1-ol 3. In the mixed solvent (THF/cis-DMTHF) 4 was isolated up to 51% yield (25% ee for (S)-4) and 3 in 42% yield (66% ee for (S)-3). In a separate experiment racemic 3 isomerized to racemic 4 in 74% yield when excess of 1 in DMTHF was used.
Highly Enantioselective Elimination of meso-Compounds
Kashihara, Hiroshi,Suemune, Hiroshi,Kawahara, Tetsuya,Sakai, Kiyoshi
, p. 1663 - 1667 (2007/10/02)
Useful chiral synthons for the synthesis of natural products, consisting of derivatives of the fixed five-membered ring system bicyclooct-2-ene, were obtained in high optical purity (87-99percent e.e.) by asymmetric elimination of the corresponding achiral (meso) trifluoromethanesulphonates with chiral N,N-dimethyl-1-phenylethylamine.However, asymmetric elimination of the chiral (+)-camphor-10-sulphonates with an achiral base resulted in low optical purity.In this enantioselective asymmetric elimination, the concave side of bicyclic ring system seems to play an important role.Asymmetric elimination of the monotriflate of cis-cyclohexane-1,4-diol resulted in a product with unsatisfactory optical purity.
