反应详情

Alkali metal phenoxides as nucleophiles proved to be superior to the combination of phenol and amine base. Sodium phenoxide furnished the corresponding allylation product with high regio- and enantioselectivity (Table 6, entries 4-6). Reaction of sodium phenoxide with methyl carbonate 1a formed the alkylation product at room temperature in a modest 40% yield because of competing trans-esterification (entry 4), but reactions with the more hindered and less reactive (E)-cinnamyl ethyl carbonate (1b of Table 6) occurred without significant competing transesterification. This combination of phenoxide and carbonate gave the branched ether in good yields with excellent regio- and enantioselectivities after 35 h at room temperature or 17 h at 50° C. (Table 6, entries 5 and 6).

1. customformed the alkylation product at room temperature in a modest 40% yield because