Allylation of C, N and O Nucleophiles

Neutral allylation with allylic carbonates has wide application in the alkylation of rather labile compounds that are sensitive to acids or bases. For example, successful C-allylation of the sensitive molecule of ascorbic acid (86) to give 87 is possible only with allyl carbonate under neutral conditions [50], However, it was shown recently that 

Allylic phosphates are more reactive than allylic acetates. Chemoselective reaction of the allylic phosphate moiety of the bis-allylic compound 88 with one equivalent of malonate, without attacking the allylic acetate moiety, takes place to give 89. Then the aminated product 90 was obtained by the addition of amine [52], 

Various cyclic compounds from three-membered rings to macrocycles have been prepared by intramolecular allylation. A typical example of this cyclization is the reaction of the monoacetate of 1,4-butenediol derivative 91 with the active methylene compound 92, which afforded the allylic alcohol 93. The three-membered chrysantemic acid derivatives 94 and 95 were then prepared after acetylation of 93, followed by Pd-catalysed intramolecular allylation [53], 

HO =/ DAc + 91 S02Ph X02Me 92 Pd(Ph3P)4 HO NL COzMe x S02Ph 1. Ac20 

Intramolecular allylation has wide application in the synthesis of macrocycles [57]. Synthesis of humulene (107) by the cyclization of allyl acetate 105 to give 106 is an early example [58]. The 14-membered ring 109 was obtained from 108 and converted to cembranolide 110 [59]. 

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