Chiral Synthesis via Organoboranes. 43. Selective Reductions. 58. Reagent-Controlled Diastereoselective Reduction of (+)- and (−)-α-Chiral Ketones with (+)- and (−)-B-Chlorodiisopinocampheylborane
摘要:
Asymmetric reduction of (+)- and (-)-alpha-chiral ketones with (+)- and (-)-B-chlorodiisopinocampheylborane provides the product alcohols in very high diastereomeric excess, with the matched pairs providing >100:1 selectivity and the mismatched pairs showing 4:1-15:1 selectivity. The high selectivity achieved even in the mismatched pairs reveals the power of the reagent to control the stereochemical outcome. The rates of the reaction of the matched pairs are faster than those of the mismatched pairs, In all the cases studied thus far, the (-)-reagent ((d)Ipc(2)BCl) and (S)ketone or the (+)-reagent ((l)Ipc(2)BCl) and (R)-ketone constitute matched pairs and the (-)-reagent and (R)-ketone or the (+)-reagent and (S)-ketone constitute mismatched pairs, A possible mechanism for the reductions is discussed.
[EN] NICOTINIC RECEPTOR NON-COMPETITIVE ANTAGONISTS<br/>[FR] ANTAGONISTES NON COMPÉTITIFS DU RÉCEPTEUR NICOTINIQUE
申请人:TARGACEPT INC
公开号:WO2014004417A1
公开(公告)日:2014-01-03
The present invention relates to compounds that modulate nicotinic receptors as non-competitive antagonists, methods for their synthesis, methods for their use, and their pharmaceutical compositions.
本发明涉及调节尼古丁受体的化合物,作为非竞争性拮抗剂,其合成方法,使用方法以及它们的药物组合物。
Mechanisms of Racemization of Camphene-8-C<sup>14</sup><sup>1</sup>
作者:John D. Roberts、Joel A. Yancey
DOI:10.1021/ja01109a037
日期:1953.7
camphene racemizes by at least two different mechanisms in the presence of hydrated titanium dioxide, pyruvic acid or aniline hydrochloride. One of these mechanisms does not cause isotope-position rearrangement of camphene-8-C^(14) and probably involves successive hydride and Wagner rearrangements. This mechanism predominates with hydrated titanium dioxide and aniline hydrochloride. Racemization of camphene-8-C^(14)
[EN] COMPOSITIONS AND METHODS RELATED TO DI-SUBSTITUTED BICYCLO[2.2.1] HEPTANAMINE-CONTAINING COMPOUNDS<br/>[FR] COMPOSITIONS ET PROCÉDÉS ASSOCIÉS À DES COMPOSÉS CONTENANT DE LA BICYCLO[2.2.1] HEPTANAMINE DI-SUBSTITUÉS
申请人:BROAD INST INC
公开号:WO2022140677A1
公开(公告)日:2022-06-30
The present disclosure relates to compositions and methods related to bicyclo[2.2.1] heptanamine-containing compounds and salts.
本申请涉及含有bicyclo[2.2.1]heptanamine化合物及其盐的组合物和方法。
Chiral Synthesis via Organoboranes. 42. Selective Reductions. 57. Efficient Kinetic Resolution of Representative α-Tertiary Ketones with <i>B</i>-Chlorodiisopinocampheylborane
作者:P. Veeraraghavan Ramachandran、Guang-Ming Chen、Herbert C. Brown
DOI:10.1021/jo951206z
日期:1996.1.1
Kinetic resolution of racemic alpha-tertiary ketones with 0.5-0.6 molar equiv of B-chlorodiisopinocampheylborane provides the product alcohols in very high diastereomeric and enantiomeric excess, with the unreacted ketone recovered in very high ee. For example, ethyl 1-methyl-8-oxocyclopentane- and -cyclohexanecarboxylates are partially reduced to recover the ketone in 91 greater than or equal to 99% ee and the product alcohols in up to 94% de, with >90% ee for the major diastereomer. Bicyclic ketones, such as 1-methyl- and 1-ethylnorcamphor, camphor, and camphenilone, are readily resolved to provide the ketone in 92 to greater than or equal to 99% ee, with the product alcohol recovered in high de and ee. Dihydrospiro[bicyclo[3.2.1]octane-2,2'(3'H)-furan]-3-one is resolved to provide the ketone in greater than or equal to 99% ee and the product alcohol in greater than or equal to 99% de. In all the cases studied, the R-isomer of the ketone is recovered when (d)Ipc(2)BCl is used for kinetic resolution, while (l)Ipc(2)BCl provides the S-ketone. Optimum conditions for obtaining the product alcohol, or the ketone, or both, in very high yields and ee have been established.
Vilkas,M.; Abraham,N.A., Bulletin de la Societe Chimique de France, 1960, p. 1196 - 1201