In the invited mini-review in EurJOC, Yang and Michel analyzed the field of Pd-catalyzed hydroformylation!
Hydroformylation of alkenes and alkynes with syngas represents a method of choice to furnish valuable aldehydes with 100% atom-economy from readily available building blocks. Although the field is dominated by Rh- and Co-catalysis; complexes of many other metals were also shown to be catalytically competent. Here we review the studies of hydroformylation under Pd-catalysis, starting from the seminal reports up to the most recent examples. Special emphasis is paid to the unique regio- and chemoselectivities of Pd-based methods, which are difficult to achieve with the conventional hydroformylation protocols. Different mechanistic proposals are presented along with a summary of their experimental andc omputational support. Finally, the user-friendly methods using surrogates of syngas are discussed as well. Overall, the mini-review aims to present unique opportunities and remaining challenges of Pd-catalyzed hydroformylation reactions for their prospective applications in fine-chemical synthesis.
In this Letter, we report the enantioselective synthesis of secondary benzylic alcohols and diarylmethanols by α-arylation of primary aliphatic and benzylic alcohols under sequential catalysis. The strategy integrates a Ru-catalyzed hydrogen transfer oxidation and a Ru-catalyzed nucleophilic addition in a one-pot fashion. The method can be applied to various alcohols and aryl nucleophiles tolerating a range of functional groups, including secondary alcohols, ketones, alkenes, esters, NH amides, tertiary amines, aryl halides, and heterocycles. Overall, the study shows the potential of multicatalysis to enable transformations that are challenging for classic catalysis.
In this Letter, we report sequential multistep protocols with up to three transition-metal complexes and a Brønsted acid that execute redox-neutral transformations for a series of alkenes, (protected) unsaturated alcohols, and aryl boronic acids, with no or with minimal intermediary workup, to furnish varied secondary benzylic alcohols in high stereoselectivity, with up to 99:1 er, dr >20:1, and 91% yield. We showed that not only the protocols are operationally simpler and up to ∼3-fold less resource-intensive than the stepwise synthesis but also that the overall yield of the product is increased (77% versus 43%) thanks to preventing cumulative losses of the materials during subsequent isolations and purifications of the intermediates.
In this Perspective article, we analyze the overarching field of multicatalysis, which we divide into three main categories: cooperative, domino, and relay catalysis. We discuss distinct challenges and opportunities of each category, which we portray with representative examples to highlight their different features. We pay special emphasis to strategies that enable transformations that are inaccessible through classic approaches. We also discuss multicatalytic systems of higher levels of complexity that further underscore the potential of multicatalysis.
The paper on the study of a highly selective and exceptionally active catalyst system that is driven by a novel activation strategy and features a unique Pd(I)–Pd(I) mechanism has been published as an Article in the Journal of the American Chemical Society. This method enables β-selective hydroformylation of a large range of alkenes and alkynes, including sensitive starting materials!
The paper on the study of dual-catalytic systems by Dawid, Yang and Karolina has been published as an Advance Online Publication: Dual-Catalytic Transition Metal Systems for Functionalization of Unreactive Sites of Molecules, Nature Catalysis (2019). Congrats to all! https://doi.org/10.1038/s41929-018-0207-1