5623-81-4Relevant articles and documents
Hydroformylation of 1,6-Dienes with Carbonylhydridotris(triphenylphosphine)rhodium
Grigg, Ronald,Reimer, Gerald J.,Wade, Alan R.
, p. 1929 - 1935 (1983)
Hydroformylation of a number of 1,6-dienes has been achieved at room temperature and atmospheric pressure using as catalyst.Octa-1,6-dienes are hydroformylated specifically at the terminal double bond and good selectivity for the n-aldehyde is observed when a 2:1 mixture of hydrogen and carbon monoxide are used.Both mono- and di-formyl derivatives are formed from 4,4-diacetylhepta-1,6-diene, with a strong preference for n-aldehydes.The effect of catalyst concentration on product distribution is reported.Octa-1,3,7-triene can be selectively hydroformylated by protecting the diene moiety as its cycloadduct with sulphur monoxide or dioxide, and whilst methylenecyclopentane undergoes regiospecific hydroformylation, methylenecyclobutane is isomerised to methylcyclobutene.
ASPARAGINE DERIVATIVES AND METHODS OF USE THEREOF
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Paragraph 00831-00832, (2021/12/31)
The present invention relates to compounds of formulas (A) and (I), pharmaceutically acceptable salts thereof, and solvates of any of them, pharmaceutical compositions comprising them, methods of preparation thereof, intermediate compounds useful for the preparation thereof, and methods of treatment or prophylaxis of diseases, in particular cancer, such as colorectal cancer, using these. (A) (I)
An Engineered Alcohol Oxidase for the Oxidation of Primary Alcohols
Heath, Rachel S.,Birmingham, William R.,Thompson, Matthew P.,Taglieber, Andreas,Daviet, Laurent,Turner, Nicholas J.
, p. 276 - 281 (2019/01/04)
Structure-guided directed evolution of choline oxidase has been carried out by using the oxidation of hexan-1-ol to hexanal as the target reaction. A six-amino-acid variant was identified with a 20-fold increased kcat compared to that of the wild-type enzyme. This variant enabled the oxidation of 10 mm hexanol to hexanal in less than 24 h with 100 % conversion. Furthermore, this variant showed a marked increase in thermostability with a corresponding increase in Tm of 20 °C. Improved solvent tolerance was demonstrated with organic solvents including ethyl acetate, heptane and cyclohexane, thereby enabling improved conversions to the aldehyde by up to 30 % above conversion for the solvent-free system. Despite the evolution of choline oxidase towards hexan-1-ol, this new variant also showed increased specific activities (by up to 100-fold) for around 50 primary aliphatic, unsaturated, branched, cyclic, benzylic and halogenated alcohols.
α-Tetrasubstituted Aldehydes through Electronic and Strain-Controlled Branch-Selective Stereoselective Hydroformylation
Eshon, Josephine,Foarta, Floriana,Landis, Clark R.,Schomaker, Jennifer M.
, p. 10207 - 10220 (2018/09/06)
Hydroformylation utilizes dihydrogen, carbon monoxide, and a catalyst to transform alkenes into aldehydes. This work applies chiral bisdiazaphospholane (BDP)- and bisphospholanoethane-ligated rhodium complexes to the hydroformylation of a variety of alkenes to produce chiral tetrasubstituted aldehydes. 1,1′-Disubstituted acrylates bearing electron-withdrawing substituents undergo hydroformylation under mild conditions (1 mol % of catalyst/BDP ligand, 150 psig gas, 60 °C) with high conversions and yields of tetrasubstituted aldehydes (e.g., 13:1 regioselectivity, 85% ee, and 99% regioselectivity and >19:1 diastereoselectivity to tetrasubstituted aldehydes at rates >50 catalyst turnovers/hour. NMR studies of the noncatalytic reaction of HRh(BDP)(CO)2 with methyl 1-fluoroacrylate enable interception of tertiary alkylrhodium intermediates, demonstrating migratory insertion to acyl species is slower than formation of secondary and primary alkylrhodium intermediates. Overall, these investigations reveal how the interplay of sterics, electronics, and ring strain are harnessed to provide access to valuable α-tetrasubstituted aldehyde synthetic building blocks by promoting branched-selective hydroformylation.
