Sulfone, allyl phenyl reaction with benzaldehyde

As shown in Scheme 3.21, treatment of ally phenyl sulfone with an excess of nBuLi affords a mixture of l,o-dilithiated allyl phenyl sulfone 109 and the 1,1-dUithiated compound 110 [78]. Quenching this mixture with benzaldehyde leads to a variety of products, including 112 and 113. However, it is interesting to note that, at 50 °C, the l,o-dilithiated species 109 is converted into the thermodynamically more stable 1,1-dUithiated allyl phenyl sulfone 110, which can undergo twofold reaction with benzaldehyde. This double lithiation coupling methodology has since been applied to various bis-electrophiles [79]. Competitive ortho-lithiation was al-... 

Initially, the allylation reaction was studied with the /V-benzyloxycarbonylamino sulfone derived from benzaldehyde and benzoyloxycarbonyl (Cbz) carbamate (Scheme 1, R1 = Ph, R = Bn). Various catalysts were screened for the allylation of benzyl phenyl(phenylsulfonyl)methylcarbamate la with allyltrimethylsilane in dichloromethane (Table 1). Among the various Bi catalysts tested, Bi(OTf)3 4H20 was shown to be the most efficient (Table 1, entry 5). BiCl3, BiBr3, Bi(OAc)3, or Bi(OCOCF3)3 did not allow the reaction to proceed and starting material was... 

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See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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