Enantioselective Preparation of 1,1‐Diarylethanes: Aldehydes as Removable Steering Groups for Asymmetric Synthesis

Abstract

Cut it out! Convenient procedures have been delineated for the synthesis of optically active, functionalized 1,1‐diarylethanes by decarbonylation of β,β‐diarylpropionaldehydes. The process can be conducted as a one‐pot 1,4‐addition/decarbonylation sequence. Aldehydes are used as removable steering groups in this new strategy for the preparation of optically active building blocks.

Asymmetric Hydrogenation of Minimally Functionalised Terminal Olefins: An Alternative Sustainable and Direct Strategy for Preparing Enantioenriched Hydrocarbons

“…Enantiopure diarylalkanes are important intermediates for the preparation of drugs and research materials 1a–c. To date, the approaches used to prepare optically active diarylalkanes have been rather laborious,1a–d but asymmetric hydrogenation may be more efficient.…”

“…Enantiopure diarylalkanes are important intermediates for the preparation of drugs and research materials 1a–c. To date, the approaches used to prepare optically active diarylalkanes have been rather laborious,1a–d but asymmetric hydrogenation may be more efficient. In this context, the Ir/phosphite–oxazoline catalytic system 18 , related to 19 , hydrogenated 1,1‐diaryl terminal olefins containing sterically different aryl substituents with excellent enantioselectivities (>99 %) (Figure 6).…”

Shuttle Catalysis—New Strategies in Organic Synthesis

“…The challenging installation of aq uaternary vinyl group was also executed by utilizing the cyano group as ar emovable steeringg roup (Scheme 15). [33] This strategy exploits the innate reactivity of acrylonitrile in ar adicalc oupling with an estrone derivative 16 using iron catalysis to furnishn itrile 17 in high stereoselectivity, [34] with the vinyl group revealed by subsequent retro-hydrocyanation. Overall, this formal hydrovinylation processa ffords the alkene 18 in 72 %y ield over 2steps.…”

Iridium catalysis: application of asymmetric reductive hydrogenation

“…26 Similarly, Rh catalysts have been used, to obtain diarylethanes, but again the substrate 35 scope was limited. 27 The application of asymmetric hydrogenation to these substrates was highly successful as shown in Table 2. 28 As can be seen, most substrates required higher pressure and temperature than commonly used.…”