01867nas a2200229   4500008004100000022001400041245017400055210006900229260000900298300001400307490000800321520099000329653003201319653001601351653002001367653002801387653001301415100002501428700002801453700002601481856013001507       2022                        eng d  a1615-415000aK3PO4-promoted cycloannulation of (E)-beta-Iodovinyl Sulfones with ortho-Hydroxy-chalcones/cinnamates for the synthesis of 2,3,4-trisubstituted 4h-benzopyran derivatives0 aK3PO4promoted cycloannulation of EbetaIodovinyl Sulfones with or  cDEC   a4080-40870 v3643 a<p>
	K3PO4-mediated cycloannulation of (E)-beta-iodovinyl sulfones with ortho-hydroxy chalcones/ortho-hydroxy cinnamates has been realized to access 2,3,4-trisubstituted-4H-benzopyran derivatives. A metal-free tandem oxa-Michael addition and cycloannulation allows the diversity-oriented synthesis of the corresponding 3-sulfonyl-4H-benzopyrans in good to high yields. More importantly, one-pot three-component reaction between (E)-beta-iodovinyl sulfones, 2-hydroxybenzaldehydes, and phosphonium ylides has been established for the synthesis of 4H-chromene derivatives in moderate to good yields. Notably, this metal-free process features a broad substrate scope and easy elaboration into numerous multifaceted chromene products, including bioactive estrone-derivative. The present protocol is sustainable at the gram scale reactions, and post-synthetic applications were also demonstrated. A plausible mechanism is also presented on the basis of existing experimental results.</p>
10a(E)-beta-Iodovinyl sulfones10aBenzopyrans10aCycloannulation10aortho-Hydroxy Chalcones10aSulfones1 aReddy, Raju, Jannapu1 aKumar, Jangam, Jagadesh1 aKrishna, Gamidi, Rama  uhttps://library.ncl.res.in/content/k3po4-promoted-cycloannulation-e-beta-iodovinyl-sulfones-ortho-hydroxy-chalconescinnamates