Cyclopropylamines as intermediates in a new method for alkylation of aldehydes and ketones

Abstract

All inorganic compounds used (perchloric acid, sodium perchlorate, sodium bromide, bromine) were reagent grade. Water used as solvent was distilled twice over alkaline potassium permanganate.

Ring-opening, cycloaddition and rearrangement reactions of nitrogen-substituted cyclopropane derivatives

“…35,36 As amines, they are also susceptible to undergo single-electron oxidation at the lone pair of the nitrogen atom, which triggers cleavage of the cyclopropane ring (Scheme 1, equation 3). This behaviour is also consistent with a homologous enamine equivalent.…”

“…35 This process is thermodynamically favourable and depending on the substrates, the removal of a protecting group under transition-metal catalysed hydrogenation conditions can therefore be accompanied by extensive cyclopropanering opening (Scheme 4). 37,38,39,40,41,42,43,44,45 …”

“…Thus, the α-substituted cyclic ketone products can be obtained at the reflux temperature of methanol (65 °C) 35. In the absence of Pd/C, these hydrolysis reactions, that sometimes proceed with good regioselectivity with respect to the cyclopropane-ring opening, require more drastic conditions: typically, 150-170 °C in a sealed tube using the same solvent (Scheme 15).…”

Photocatalytic Reaction of Diazo Compounds with Aldehydes

“…Kuehne andK ing reported that treatment of the preformed enaminesw ith diazomethane in the presence of CuCl led to cyclopropylamines which aftert hermal hydrolysis gave alkylated carbonylc ompoundsa s am ixture of regioisomeric products. [45] It was reported that in the presence of Rh(II) complex the reaction of a-diazo ketones with vinyl ethers affordedc yclopropane derivatives which underwent ring-opening leading to 1,4-diketones. [46] Such cyclopropanes bearing bothe lectron-donating and electron-withdrawing groups were found to be easily cleaved.…”

“…[46] Such cyclopropanes bearing bothe lectron-donating and electron-withdrawing groups were found to be easily cleaved. [45][46][47][48][49] We have prepared acyclopropylamine derivative using areported methodology and subjected it to the developed reaction conditions (Scheme 4).…”