Rh(I)-catalyzed CO gas-free carbonylative cyclization of organic halides with tethered nucleophiles using aldehydes as a substitute for carbon monoxide

New Pentacoordinated Rhodium Species as Unexpected Products during the In Situ Generation of Dimeric Diphosphine‐Rhodium Neutral Catalysts

“…[19] Upon coordination of the chloride, the dihedral angle P-Rh-P/C M -Rh-C M widens from for example, 10.6 8 in [Rh(cod)(dppp)][BF 4 ] [20] to 20.7 8 in [RhCl(cod)(dppp) ]. [5] In the latter, the RhÀP bond length increases of about 0.35 (in the former complexes of just 0.05 ). On the other hand, the RhÀCl distance, 2.40 , falls within the expected range of Rh-terminal Cl bond lengths.…”

“…[14] For the ligand 4,5-bis(diphenylphosphino)-9,9dimethylxanthene (XANTPHOS) the structure of [RhCl(cod)-(xantphos)] has been published. [5] Identification of the precatalyst generated "in situ" is essential for understanding of the ensuing catalytic processes and the factors affecting activity and selectivity. Comprehension of possible deactivation phenomena is the prerequisite for improving reaction rates.…”

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

“…In the first of these it had been shown that aldehydes may participate in Pauson-Khand reactions, [19] and the second involved the carbonylative cyclizations of benzylic alcohols. [20] These results suggested that coupling of the decarbonylation reaction to either of the carbonylative cyclizations could prove useful for our own objectives. Indeed, the decarbonylation reaction of 1 a could be performed neat in a sealed vessel at 100 8C in the presence of 2 equiv [3-(allyloxy)prop-1-ynyl]benzene (Scheme 2) to furnish 2 a in 78 % yield.…”

CO Gas‐free Intramolecular Cyclocarbonylation Reactions of Haloarenes Having a C‐Nucleophile through CO‐Relay between Rhodium and Palladium

“…Our previous reports on the CO gas-free cyclocarbonylation of haloarenes having ac arbon-nucleophile moiety with aldehydes clarified that the use of as ingle rhodium(I) complex, [RhCl(cod)] 2 ,a nd dppp (1,3-bis(diphenylphosphino)propane) catalyzes the transfer of ac arbonyl group from 2-naphthaldehyde to the iodobenzene derivative 1a to give the cyclocarbonylated product 2 and more available bromo-derivative 1b is not carbonylated (Scheme 1a and b). [11,12] We began our study with the reaction of bromobenzene 1b containing am alonatenucleophile with an aldehyde with the goal of achieving CO gas-free cyclocarbonylation. The use of Pd(dppp) 2 as as ingly catalystr esulted in no formation of 2,s imilart ot hat for of [RhCl(cod)] 2 /dppp (b and c).…”