[摘要]：Highly reactive 1:1 intermediates were produced in the reaction of Ph3P and dialkyl acctylenedicarboxylates (=dialkyl but-2-ynedioates). Protonation of these intermediates by alcohols (2,2,2-trichloroethanol, propargyl alcohol (=prop-2-yn-1-ol), MeOH, benzyl alcohol, and allyl alcohol (=prop-2-en-1-ol) led to vinyltriphenylphosphonium salts 4, which undenvent a Michael addition reaction with the conjugate base to produce the corresponding stabilized phosphonium ylides 5 (Scheme). Wittig reaction of the stabilized phosphonium ylides with ninhydrin (6) led to the corresponding densely functionalized 2H-indeno[2,1-b]furans 10 in fairly good yields (Table 1). The structures of the final products were confirmed by IR, H-1- and C-13-NMR spectroscopy, and mass spectrometry. The configuration of dimethyl 8,8a-dihydro-8-oxo-8a-(2,2,2-trichloroethoxy)-2H-indeno[2,1-b]furan-2,3-dicarboxylate (10a) was established by a single-crystal X-ray structure determination. establishing that the one-pot multicomponent Coll de it sat ion reaction was completely, diastereoselective.
