195380-06-4Relevant academic research and scientific papers
Synthesis of hydroxy pyrrolidines and piperidines via free-radical cyclisations
Parsons, Andrew F.,Pettifer, Robert M.
, p. 651 - 660 (2007/10/03)
The tin hydride-mediated cyclisation of a variety of α- and β-amino aldehydes to form substituted pyrrolidines and piperidines under mild, neutral reaction conditions has been investigated. The amino aldehyde precursors, prepared from the corresponding amino ester or alcohol, are purified or immediately reacted with Bu3SnH-AIBN in boiling benzene. The method is shown to be general and cyclisation of the intermediate O-stannyl ketyl is observed using a variety of (electron poor or rich) acceptor carbon-carbon double bonds to afford hydroxy-pyrrolidines or -piperidines after work-up. Related cyclisations using an alkyne or α,β-unsaturated amide radical acceptor are shown to be problematic and low-yielding. Radical cyclisation of allylic O-stannyl ketyls, generated from reaction of α,β-unsaturated ketones with tin hydride, are also shown to have application in pyrrolidine/piperidine synthesis. A dilution study suggests that the cyclisation onto a cinnamyl double bond is irreversible.
Radical cyclisation of amino aldehydes leading to hydroxy pyrrolidines and piperidines
Parsons, Andrew F.,Pettifer, Robert M.
, p. 5907 - 5910 (2007/10/03)
The cyclisation of amino aldehydes using Bu3SnH in boiling benzene is reported. The reaction proceeds via addition of a tributyltin radical to the aldehyde forming an O-stannyl ketyl and radical cyclisation onto electron poor or rich double bonds gives rise to hydroxy pyrrolidines and piperidines.
