Diels-Alder reactions of phospholes

The Diels-Alder reaction of phospholes was not studied extensively. It was known, however, that the cycloadditionoftheMatheyphosphole(46)withA-phenyhnaleimide afforded 7-phosphanorbomene 47 (Scheme 11) [50], Similar reactions with fuma-ronitrile or with another unit of phosphole led to products with the same anti configuration of the bridging P-moiety [51, 52],... 

The vast majority of bicyclic phosphole derivatives with norbornene- and norbornadiene-derived skeletons are prepared via classical [4+2] cycloaddition reactions of phospholes. While Diels-Alder reactions of phospholes with CN 4 (e.g., oxides and sulfides) are common through direct reaction with dienophiles, this type of reaction is comparatively rare for CN 3 phospholes (see Section 3.15.5.1.4). 

Leung et al. [152-167] proposed the Diels-Alder reaction of phospholes with various dienophiles catalyzed by palladium complexes 235 as a method for the synthesis of chiral phosphines. The chiral compounds containing S)-ortho-(l-dimethylaminoethyl)-naphthalene palladium 235 were complexed with diene, for example with 3,4-dimethyl-1-phenylphosphole, which then entered into the Diels-Alder reaction with dienophiles (W,W-dimethylacrylamide, styrene, and others) to result in diastereoisomers of entio-amidophosphanorbomenon complexes 236 and 237. After separation, purification, and decomplexation, the... 

---