99797-53-2Relevant academic research and scientific papers
Electronic and steric control in regioselective addition reactions of organolithium reagents with enaldimines
Tomioka,Shioya,Nagaoka,Yamada
, p. 7051 - 7054 (2007/10/03)
A reaction mode of imines derived from naphthalene-1-carbaldehyde and acyclic α,β-unsaturated aldehydes with organolitium reagents was dependent on the characteristic nature of a substituent on the imine nitrogen atom. An imine having an electron-withdrawing aryl group on the nirtogen atom behaves as a 1,2-directing imine toward organolithium reagents. In contrast, an imine bearing an alkyl or a bulky aryl group favors 1,4-addition of organolithium reagents. Electronic and steric tuning of a substituent on the imine nitrogen atom for a reaction mode was rationalized on the basis of molecular orbital calculations.
A one-flask synthesis of dihydronaphthalenemethanols by directed addition of organolithium reagents to BHA naphthalenecarboxylates
Shindo, Mitsuru,Koga, Kenji,Asano, Yasutomi,Tomioka, Kiyoshi
, p. 4955 - 4968 (2007/10/03)
The 1,4-addition reaction of organolithium reagents with 2,6-bis(tert- butyl)-4-methoxyphenyl naphthalenecarboxylates gave regioselectively substituted dihydronaphthalenecarboxylates in high yields. Successive treatment of the esters with organolithiums in THF, lithium triethylborohydride, methyl iodide, and finally sodium borohydride in methanol, provided vegio- and stereoselectively the corresponding 1,1,2- and 1,2,2-trisubstituted dihydronaphthalenylmethanols in good yields. This one- flask process is constituted from a sequence of five reactions involving a reductive generation of an aldehyde metal enolate from a ketene as the key step.
Design, synthesis, and application of a C2 symmetric chiral ligand for enantioselective conjugate addition of organolithium to α,β-unsaturated aldimine
Shindo, Mitsuru,Koga, Kenji,Tomioka, Kiyoshi
, p. 9351 - 9357 (2007/10/03)
A C2 symmetric chiral diether ligand, (1R,2R)-1,2-dimethoxy-1,2- diphenylethane, was designed and synthesized on the basis of the concept of an asymmetric oxygen atom. Mediated by the chiral diether, high enantioselectivities were achieved in conjugate addition of organolithiums to naphthaldehyde imine and cyclic and acyclic α,β-unsaturated aldimines. The absolute configuration of the product is predictable by the model.
Asymmetric addition of aryllithiums to naphthalene BHA-esters catalyzed by a chiral ligand
Tomioka,Shindo,Koga
, p. 681 - 682 (2007/10/02)
In the presence of both stoichiometric and catalytic amounts of a chiral dieter 1, aryllithiums reacted with BHA-esters of naphthalenecarboxylic acids 2, 5 to afford the corresponding adducts 4, 6 in high ee.
Reductive Generation of Aldehyde Metal Enolate from Ketene. A One-Flask Process to 1,1,2- and 1,2,2-Trisubstituted Dihydronaphthalenes from 1- and 2-Naphthalenecarboxylates
Tomioka, Kiyoshi,Shindo, Mitsuru,Koga, Kenji
, p. 2276 - 2277 (2007/10/02)
Successive treatment of 2,6-di-tert-butyl-4-(methoxyphenyl)-1- and -2-naphthalenecarboxylates (BHA esters) (1, 2) with organolithium in THF, lithium triethylborohydride in refluxing THF, methyl iodide-HMPA, and finally sodium borohydride in MeOH provided regio- and stereoselectively 1,1,2- and 1,2,2-trisubstituted dihydronaphthalenes (3, 4), respectively, in good yields.This one-flask process is constituted from a sequence of five reactions involving reductive generation of aldehyde metal enolate from ketene as a key step.
