138907-36-5Relevant academic research and scientific papers
Divergent reactivity of homologue ortho-Allenylbenzaldehydes controlled by the tether length: Chromone versus chromene formation
Alcaide, Benito,Almendros, Pedro,Fernndez, Israel,Del Campo, Teresa Martnez,Naranjo, Teresa
supporting information, p. 1533 - 1541 (2015/01/30)
The divergent behavior of two homologue allenals, namely, 2-(buta-2,3-dienyloxy)- and 2-(propa-1,2-dienyloxy)benzaldehydes, as cyclization substrates is described. 2-(Buta-2,3-dienyloxy)benzaldehydes suffers a formal allenic carbocyclization reaction to afford chromenes, whereas 2-(propa-1,2-dienyloxy)benzaldehydes react to yield chromones. The formation of chromenes is strictly a formal hydroarylation process divided into two parts, namely, allenic Claisen-type rearrangement and oxycyclization. An unknown N-heterocyclic carbene (NHC)-catalyzed allenic hydroacylation reaction must be invoked to account for the preparation of chromones. ortho-Allenylbenzaldehydes bearing either electron-donating substituents or electron-withdrawing substituents worked well to afford both the hydroarylation and hydroacylation products. This unexpected difference in reactivity can be rationalized by means of density functional theory calculations.
CuI-catalyzed synthesis of functionalized terminal allenes from 1-alkynes
Luo, Hongwen,Ma, Shengming
, p. 3041 - 3048 (2013/06/27)
Relative to our original protocol that uses CuI (0.5 equiv.), paraformaldehyde (2.5 equiv.), and dicyclohexylamine (1.8 equiv.), a facile and efficient protocol for the gram-scale synthesis of functionalized terminal allenes by using CuI (7.5-10 mol-%), p
