41793-01-5Relevant articles and documents
Pd-Catalyzed Redox Divergent Coupling of Ketones with Terpenols
Zhao, Chao-Yang,Ji, Ding-Wei,Zheng, Hao,He, Gu-Cheng,Liu, Heng,Hu, Yan-Cheng,Chen, Qing-An
, p. 6825 - 6834 (2021/06/28)
Redox diversity is a common and important feature of nature. Herein, a Pd-catalyzed redox divergent coupling of ketones with terpenols has been developed to access α-substituted ketones with varying degrees of unsaturation. The control of oxidation states of the product is facilitated by employing different additives. With the aid of BnOH as an external hydrogen source, a reductive coupling pathway is thermodynamically favored. The use of LiBr as the additive will reduce the reactivity of Pd-H to divert the selectivity toward α,β-unsatuated ketones. By switching the solvent from toluene to chlorobenzene, the active species Pd-H will be fully quenched to enable oxidative coupling. Gram-scale reaction with lower catalyst loading (0.5 mol %) was also accomplished to highlight the practicability of this protocol. Furthermore, detailed experimental studies were carried out to elucidate the reaction mechanism and the factors enabling manipulation of the redox selectivity. This redox divergent coupling protocol provides an important complement for known precedents on Tsuji-Trost allylation of ketones.
Synthesis and cellular effects of cycloterpenals: Cyclohexadienal-based activators of neurite outgrowth
Bench, Bennie J.,Tichy, Shane E.,Perez, Lisa M.,Benson, Jenna,Watanabe, Coran M.H.
scheme or table, p. 7573 - 7581 (2009/04/04)
An unusual class of diterpenoid natural products, 'cycloterpenals' (with a central cyclohexadienal core), that arise in nature by condensation of retinoids and other isoprenes, have been isolated from a variety of organisms including marine sponges as well as from the human eye. A milk whey protein has also demonstrated the formation of a cycloterpenal derived from β-ionylidineacetaldehyde. Here, we generate a synthetic library of these molecules where we detail reaction conditions required to effect cross condensation of α,β-unsaturated aldehydes as opposed to homodimerization. The ability of this class of molecules to activate neurite outgrowth activity is reported.
Initial interaction of triphenylphosphonium-2-propenylide with prenal prior to Wittig olefination
Schneider, David F.,Venter, Abraham C.
, p. 3067 - 3081 (2007/10/03)
The interaction of triphenylphosphonium-2-propenylide (2) with prenal (6) is shown to proceed via initial C(γ)-C1 addition, followed by dissociation of the coupling product and C(α)-C1 recombination to produce the corresponding betaine, which eliminates triphenyphosphine oxide to yield (E)- and (Z)-6-methyl-1,3,5-triene (7a,b) as the Wittig olefination products.
