摘要:
A series of conjugated allenones (11b, 12b, 13c; 18a; 18b; 19b, 20b, AB, and 27d) were prepared by [2,3] Wittig rearrangement of (propargyloxy) acetic acids or [(progargyloxy)methy]stannanes followed by oxidation of the resultant allenylcarbinols. These allenones were readily cyclized to 2,3,5-trisubstituted furans upon treatment with AgNO3-CaCO3 in aqueous acetone. Under these conditions 2-(hydroxymethyl)-3,5-dialkylfurans self-condensed to give 2,2'-difurylmethanes.