Synthesis of Enones and Enals via Dehydrogenation of Saturated Ketones and Aldehydes

Abstract

A general, efficient and economic palladium-catalyzed dehydrogenation to form enones or enals has been developed. The approach possesses extremely broad substrate scope including various linear or cyclic saturated ketones and aldehydes. The protocol is ligand-free, and molecular oxygen is used as the sole clean oxidant in the reaction. Due to mild reaction conditions, good functional group compatibility, and versatile utilities of enones and enals, the method can be applied in the late-stage synthesis of natural products, pharmaceuticals and fine chemicals.

Synthesis of Flavanones via Palladium(II)-Catalyzed One-Pot β-Arylation of Chromanones with Arylboronic Acids

“…Therefore, they showed good to excellent functional group compatibility and the feasibility of late-stage functionalization which has been the central focus in medicinal chemistry and chemical biology fields. However, chromones are sometimes prepared from chromanones, a class of simple ketones, via additional oxidation processes and generally not unmanageable because they possess reactive α,β-unsaturated carbonyl and enol ether which chromanones do not have. Therefore, chromanones might be applicable substrates to the synthesis of flavanones, if it is possible to use them.…”

Structural derivatization strategies of natural phenols by semi-synthesis and total-synthesis

“…Dehydrogenation of propiophenone fragments always employ 2,3-dicyano-5,6-dichlorobenzoquinone (DDQ) as oxidant [ 121 ]. Recently, an efficient, economic and general Pd(OAc) 2 -catalyzed dehydrogenation was developed using molecular oxygen as the oxidant [ 122 ], offering a new option for this transformation. 1,2-addition and 3,4-addition of acrylophenone fragments were also conducted in similar way with those of phenylketone and allylbenzene fragments which has been respectively reviewed in Schemes 12 and 6 .…”

Mesoionic Carbene (MIC)-Catalyzed H/D Exchange at Formyl Groups

“…[11][12][13][14][15] Because of their versatility as organic building blocks, deuterated aldehydes (R-CDO) are frequently employed in these experiments and as intermediates for the synthesis of other deuterated compounds. [16][17][18][19][20][21] A number of approaches, such as the reduction of carboxylic acid derivatives [22][23][24][25] (Figure 1A) and the carbonylation of aryl halides 26 (Figure 1B), have been reported for the preparation of deuterated aldehydes. However, these reactions not only use expensive transition metal catalysts and/or deuterated reductants, but they also usually require multiple steps.…”