64245-70-1Relevant articles and documents
Synthesis of phenyl analog of retinoic acid methyl ester proceeding from 3-(bromomethyl)but-3-enal diethylacetal
Masyuk,Mineeva
, p. 1642 - 1650 (2017/12/29)
Aromatic analog of retinoic acid methyl ester was prepared using a convenient prenylating agent, 3-(bromomethyl)but-3-enal diethylacetal, and Barbier reaction in the key stage of building up the carbon chain of target molecules. A version is offered of the synthesis of methylidene analog of aromatic retinoic acid.
Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E, Z)-dienals: Stereoelectronic role of trans effect in a metal-mediated pericyclic process and a shift from homogeneous to heterogeneous catalysis during a one-pot reaction
Vidhani, Dinesh V.,Krafft, Marie E.,Alabugin, Igor V.
supporting information, p. 352 - 364 (2014/01/17)
The combination of experiments and computations reveals unusual features of stereoselective Rh(I)-catalyzed transformation of propargyl vinyl ethers into (E,Z)-dienals. The first step, the conversion of propargyl vinyl ethers into allene aldehydes, proceeds under homogeneous conditions via a cyclization-mediated mechanism initiated by Rh(I) coordination at the alkyne. This path agrees well with the small experimental effects of substituents on the carbinol carbon. The key feature revealed by the computational study is the stereoelectronic effect of the ligand arrangement at the catalytic center. The rearrangement barriers significantly decrease due to the greater transfer of electron density from the catalytic metal center to the CO ligand oriented trans to the alkyne. This effect increases electrophilicity of the metal and lowers the calculated barriers by 9.0 kcal/mol. Subsequent evolution of the catalyst leads to the in situ formation of Rh(I) nanoclusters that catalyze stereoselective tautomerization. The intermediacy of heterogeneous catalysis by nanoclusters was confirmed by mercury poisoning, temperature-dependent sigmoidal kinetic curves, and dynamic light scattering. The combination of experiments and computations suggests that the initially formed allene-aldehyde product assists in the transformation of a homogeneous catalyst (or a cocktail of catalysts) into nanoclusters, which in turn catalyze and control the stereochemistry of subsequent transformations.
Stereocontrolled synthesis of (E,Z)-dienals via tandem Rh(I)-catalyzed rearrangement of propargyl vinyl ethers
Vidhani, Dinesh V.,Krafft, Marie E.,Alabugin, Igor V.
, p. 4462 - 4465 (2013/09/24)
A novel Rh(I)-catalyzed approach to functionalized (E,Z) dienals has been developed via tandem transformation where a stereoselective hydrogen transfer follows a propargyl Claisen rearrangement. Z-Stereochemistry of the first double bond suggests the involvement of a six-membered cyclic intermediate whereas the E-stereochemistry of the second double bond stems from the subsequent protodemetalation step giving an (E,Z)-dienal.
