High yields of diazabicycloalkanes and oxazabicycloalkanes containing medium and large rings from rhodium-catalysed hydroformylation reactions without the need for high dilution conditions

Abstract

Rhodium-catalysed reactions of N-alkenyl-1,3-diaminopropanes and N-alkenylaminoethanols give diazabicycloalkanes and oxazabicycloalkanes containing medium or large rings in excellent yields.

A General Approach to Aza‐Heterocycles by Means of Domino Sequences Driven by Hydroformylation

“…Initially, the optimization work was done by using compound 2. All the possible products (11)(12)(13)(14)(15)(16) that can be formed during the hydroformylation of 2 are reported in Table 1. As the clean generation of the linear aldehyde 11 by hydroformylation is crucial for the domino sequence, different variables, such as the solvent, the ligand for Rh I , the temperature, acid additives, and the nature of the conditions needed for the domino sequence were addressed.…”

Stereoselective Multicomponent Assembly of Enantiopure Oxazolopiperidines and -azepines

“…As a preliminary study, we examined the viability of the sequence via the intramolecular CHC process , and investigated the terminal hydroformylation of alkene 6 (Scheme a), prepared in 52% yields by microwave-assisted reaction of ( R )-phenylglycinol 5a with 4-bromobutene (1 equiv of triethylamine and TBAI) . Next, compound 6 was submitted to hydroformylation in THF for 4 h at 65 °C with the conditions used in our recent work on the synthesis of polysubstitued piperidines: Rh(CO) 2 acac as the precatalyst and biphephos as the ligand in a pressurized autoclave with syngas (H 2 /CO: 1/1, 4 bar).…”