Rhodium-catalyzed intermolecular chelation controlled alkene and alkyne hydroacylation: synthetic scope of beta-S-substituted aldehyde substrates.
The use of beta-S-substituted aldehydes in rhodium-catalyzed intermolecular hydroacylation reactions is reported. Aldehydes substituted with either sulfide or thioacetal groups undergo efficient hydroacylation with a variety of electron-poor alkenes, such as enoates, in Stetter-like processes and with both electron-poor and neutral alkynes. In general, the reactions with electron-poor alkenes demonstrate good selectivity for the linear regioisomer, and the reactions with alkynes provide enone products with excellent selectivity for the E-isomers. The scope of the process was shown to be broad, tolerating a variety of substitution patterns and functional groups on both reaction components. A novel CN-directing effect was shown to be responsible for reversing the regioselectivity in a number of alkyne hydroacylation reactions. Catalyst loadings as low as 0.1 mol % were achievable.
Willis
Michael C
MC
Department of Chemistry, University of Bath, Bath BA2 7AY, UK. m.c.willis@bath.ac.uk
Randell-Sly
Helen E
HE
Woodward
Robert L
RL
McNally
Steven J
SJ
Currie
Gordon S
GS
D000447:Aldehydes / Q000737:chemistry*; D000475:Alkenes / Q000737:chemistry*; D000480:Alkynes / Q000737:chemistry*; D002384:Catalysis; D007659:Ketones / Q000138:chemical synthesis* / Q000737:chemistry; D015394:Molecular Structure; D012238:Rhodium / Q000737:chemistry*; D013237:Stereoisomerism
D000447:Aldehydes; D000475:Alkenes; D000480:Alkynes; D007659:Ketones; D012238:Rhodium