Allylphosphine oxides

Details of various routes to allylphosphine oxides (43) have been reported, and the subsequent synthesis of 1,3-dienes has been illustrated by many examples.37 Also described are stereochemical aspects of these diene syntheses and of subsequent Diels-Alder cycloaddition reactions.37 High regioselectivity is observed in migrations of the diphenylphosphinoyl group from unsymmetrical sites, as in (44), in that both products have a double bond exocydic to the cyclohexane ring.38... 

Asymmetric hydroarylation of diphenylphosphinylallenes [Ph2P(0)]C(R)=C=CH2 with arylboronic acids ArB(OH)2, catalysed by an Rh-BINAP complex, has been shown to proceed in high yields with high regio- and enantio-selectivity to afford chiral allylphosphine oxides [Ph2P(0)]CH(R)C(Ar)=CH2 of up to 98% ee. A Tr-allylrhodium complex has been identified as the key intermediate.109... 

Allylphosphine oxides may be used to make allyl alcohols by the reductive removal of the Ph2PO group with LAH. The reaction involves transposition of the double bond (equation Li(Bu 0)3AlH breaks selectively the C—P phosphonate bond, and this reagent is chemoselective and can... 

Further applications of allylphosphine oxides to diene synthesis have been described. Examples are shown in Scheme 10 of the reactions of cw-but-2-enyl-... 

Within the total synthesis of new A-ring analogues of la,25-dihydroxy-vitamin D3, an acrylic ester derivative was transformed to an allylphosphine oxide via reduction, halogenation and P-functionalization (Scheme 14). ... 

Diphenyl-allylphosphine oxide derivatives were utilized in Wittig-Horner analogous reactions leading to the analogues of 19-norvitamin D3 (Scheme 44). ... 

The triphenylphosphine-catalyzed reaction of allenyl-diphenylphos-phine oxide with N- and C-nucleophiles gave y-substituted allylphosphine oxides. Scheme 59 shows the outcome of the reaction with phthalimide. " The bisoxide of BINAP was modified by double bromination using NBS in an ionic liquid (hexylmethylimidazolium PFs or Ntfa) (Scheme 60). The resolution of 2,2 -bis(diphenylphosphinoyl)-l,l -binaphthyl was accomplished via an inclusion complex with chiral 2,2 -dihydroxy-l,l -binaphthyl... 

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