162489-18-1Relevant articles and documents
Catalytic asymmetric intramolecular homologation of ketones with α-diazoesters: Synthesis of cyclic α-Aryl/Alkyl β-ketoesters
Li, Wei,Tan, Fei,Hao, Xiaoyu,Wang, Gang,Tang, Yu,Liu, Xiaohua,Lin, Lili,Feng, Xiaoming
supporting information, p. 1608 - 1611 (2015/01/30)
A catalytic asymmetric intramolecular homologation of simple ketones with α-diazoesters was firstly accomplished with a chiral N,N′-dioxide-Sc(OTf)3 complex. This method provides an efficient access to chiral cyclic α-aryl/alkyl β-ketoesters containing an all-carbon quaternary stereocenter. Under mild conditions, a variety of aryl- and alkyl-substituted ketone groups reacted with α-diazoester groups smoothly through an intramolecular addition/rearrangement process, producing the β-ketoesters in high yield and enantiomeric excess.
Chiral Synthesis via Organoboranes. 42. Selective Reductions. 57. Efficient Kinetic Resolution of Representative α-Tertiary Ketones with B-Chlorodiisopinocampheylborane
Ramachandran, P. Veeraraghavan,Chen, Guang-Ming,Brown, Herbert C.
, p. 88 - 94 (2007/10/03)
Kinetic resolution of racemic α-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-2-oxocyclopentane- and cyclohexanecarboxylates are partially reduced to recover the ketone in 91 to >/=99percent ee and the product alcohols in up to 94percent de, with >90percent 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 >/=99percent ee, with the product alcohol recovered in high de and ee.Dihydrospirooctane-2,2'(3'H)-furan>-3-one is resolved to provide the ketone in >/=99percent ee and the product alcohol in >/=99percent de.In all the cases studied, the R-isomer of the ketone is recovered when dIpc2BCl is used for kinetic resolution, while lIpc2BCl 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.
Asymmetric Alkylation Using Chiral Cyclic Diols to Prepare a Quaternary Carbon
Kato, Keisuke,Suemune, Hiroshi,Sakai, Kiyoshi
, p. 3315 - 3326 (2007/10/02)
Asymmetric alkylation of cyclic and acyclic β-keto ester acetals (4, 5, 13, 14, and 18) with C2-symmetric cycloalkane-1,2-dioxy moiety proceeded in a highly diastereoselective manner to afford enol ethers (9-12, 15-17, 19a-c) with a chiral quat