PubMed:3442778
Annnotations
{"target":"https://pubannotation.org/docs/sourcedb/PubMed/sourceid/3442778","sourcedb":"PubMed","sourceid":"3442778","source_url":"http://www.ncbi.nlm.nih.gov/pubmed/3442778","text":"Palladium(0)-assisted synthesis of C-glycopyranosyl compounds.\nTetrakis(triphenylphosphine)palladium(0) effects the regio- and stereo-selective alkylation of 2-acetoxy-5,6-dihydro-2H-pyrans and 1-S-acetyl-1-thiohex-2-enopyranosides. Use of stabilized carbanions resulted in the formation of alkylated dihydropyrans with net retention at the oxygen-bearing carbon atom. Examples include the preparation of 2-[acetamidobis(ethoxycarbonyl)methyl]-5,6-dihydro-2H-pyran, 2-[acetamidobis(methoxycarbonyl)methyl]-6-ethoxy-5,6-dihydro-2H-py ran, and 2-[acetamidobis(methoxycarbonyl)methyl]-6-methoxymethyl-5,6-dihydr o-2H- pyran. Use of nonstabilized carbanions, such as arylzinc chlorides, resulted in the formation of alkylated dihydropyrans and C-glycosyl compounds with net inversion at the oxygen-bearing carbon atom. Examples include the preparation of 2-[(6-ethoxy-5,6-dihydro-2H-pyranyl)methyl]-4,4-dimethyl-2-oxazoli ne, trans-methoxymethyl-2-phenyl-5,6-dihydro-2H-pyran, trans-methoxymethyl-2-vinyl-5,6-dihydro-2H-pyran, trans-2-[2,2-bis(ethoxy)ethyl]-6-methoxymethyl-5,6-dihydro-2H-pyran, (4,6-di-O-methyl-2,3-dideoxy-alpha-D-erythro-hex-2-enopyranosyl)be nzene, (2,3-dideoxy-4,6-di-O-methyl-beta-D-erythro-hex-2-enopyranosyl)ben zene, 1-(2,3-dideoxy-4,6-di-O-methyl-alpha and -beta-D-erythro-hex-2-enopyranosyl)naphthalene, 4-(2,3-dideoxy-4,6-di-O-methyl-alpha- and -beta-D-erythro-hex-2-enopyranosyl)toluene, and 1-(2,3-trideoxy-4-O-methyl-alpha-L-erythro-hex-2-enopyranosyl)naph thalene.","tracks":[{"project":"sentences","denotations":[{"id":"TextSentencer_T1","span":{"begin":0,"end":62},"obj":"Sentence"},{"id":"TextSentencer_T2","span":{"begin":63,"end":232},"obj":"Sentence"},{"id":"TextSentencer_T3","span":{"begin":233,"end":368},"obj":"Sentence"},{"id":"TextSentencer_T4","span":{"begin":369,"end":621},"obj":"Sentence"},{"id":"TextSentencer_T5","span":{"begin":622,"end":814},"obj":"Sentence"},{"id":"TextSentencer_T6","span":{"begin":815,"end":1493},"obj":"Sentence"},{"id":"T1","span":{"begin":0,"end":62},"obj":"Sentence"},{"id":"T2","span":{"begin":63,"end":232},"obj":"Sentence"},{"id":"T3","span":{"begin":233,"end":368},"obj":"Sentence"},{"id":"T4","span":{"begin":369,"end":621},"obj":"Sentence"},{"id":"T5","span":{"begin":622,"end":814},"obj":"Sentence"},{"id":"T6","span":{"begin":815,"end":1493},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"attributes":[{"subj":"TextSentencer_T1","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T2","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T3","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T4","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T5","pred":"source","obj":"sentences"},{"subj":"TextSentencer_T6","pred":"source","obj":"sentences"},{"subj":"T1","pred":"source","obj":"sentences"},{"subj":"T2","pred":"source","obj":"sentences"},{"subj":"T3","pred":"source","obj":"sentences"},{"subj":"T4","pred":"source","obj":"sentences"},{"subj":"T5","pred":"source","obj":"sentences"},{"subj":"T6","pred":"source","obj":"sentences"}]}],"config":{"attribute types":[{"pred":"source","value type":"selection","values":[{"id":"sentences","color":"#ec93c4","default":true}]}]}}