Linked Life Data

19572584

Source:http://linkedlifedata.com/resource/pubmed/id/19572584

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2009-9-3
pubmed:abstractText
The reaction of salicylaldehydes with allenylphosphonates in the presence of a base leads to a variety of phosphono-chromenes and allylic phosphonates. Optimization of reaction conditions reveals that DBU (base) in DMSO (solvent) is the best combination in most cases, with DBU acting as an organocatalyst. PEG-400 also gave good results, but the yields were slightly lower than that in DMSO. Several of the key products have been characterized by single-crystal X-ray crystallography. Interconversion of E and Z isomers of phosphono-chromenes is demonstrated by (31)P NMR spectroscopy. A novel P-C bond cleavage reaction of some of these chromenes leading to substituted enones is also reported. In a few cases, phenol addition products are also isolated. In order to probe the pathways in the latter reaction, allenylphosphonates have also been treated with activated phenols in the presence of base to selectively afford either allylic phosphonyl ethers or vinylic phosphonyl ethers depending on the substituents on the allenylphosphonate. Theoretical calculations were consistent with experimental results. Finally, utilization of allylic phosphonyl ether in the Horner-Wadsworth-Emmons reaction to afford substituted trans-1,3-butadiene in good yields is demonstrated.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
1520-6904
pubmed:author
pubmed:issnType
Electronic
pubmed:day
7
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
5395-404
pubmed:meshHeading
pubmed:year
2009
pubmed:articleTitle
Reactivity of allenylphosphonates toward salicylaldehydes and activated phenols: facile synthesis of chromenes and substituted butadienes.
pubmed:affiliation
School of Chemistry, University of Hyderabad, Hyderabad 500 046, A. P., India.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't