{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2025,12,10]],"date-time":"2025-12-10T15:20:59Z","timestamp":1765380059584,"version":"build-2065373602"},"reference-count":71,"publisher":"Wiley","issue":"32","license":[{"start":{"date-parts":[[2006,9,22]],"date-time":"2006-09-22T00:00:00Z","timestamp":1158883200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Chemistry A European J"],"published-print":{"date-parts":[[2006,11,6]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>A highly chemoselective sequence of Stille and Heck couplings on the heterocyclic bromoenol triflates <jats:bold>2\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> with the bicycloalkenylstannanes <jats:italic>cis\u2010<\/jats:italic><jats:bold>3<\/jats:bold> and <jats:italic>trans\u2010<\/jats:italic><jats:bold>3<\/jats:bold> furnished the intermediate bromobutadienes <jats:bold>4\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> in good yields ranging from 73\u201394\u2009%. A modified Heck coupling protocol employing the palladacycle <jats:bold>8<\/jats:bold> and an additional bidentate ligand such as 1,4\u2010bis(diphenylphosphinyl)butane allowed a significant reduction in catalyst loading while still obtaining the heterocyclic 1,3,5\u2010hexatrienes <jats:bold>5\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> in good yields (71\u201394\u2009%). The unsymmetrically substituted 1,3,5\u2010hexatrienes <jats:bold>5\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> in solution underwent 6\u03c0\u2010electrocyclizations following an optimized microwave\u2010heating protocol to yield the steroidal tetracycles <jats:italic>cis<\/jats:italic>\u2010<jats:bold>7\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> and <jats:italic>trans\u2010<\/jats:italic><jats:bold>7\u2009b<\/jats:bold> (59\u201369\u2009%). Tetracycles <jats:italic>cis\u2010<\/jats:italic><jats:bold>7\u2009a<\/jats:bold>\u2013<jats:bold>c<\/jats:bold> are the products of a subsequent 1,5\u2010hydrogen shift to the thermodynamically more stable, more highly substituted diene units. Removal of the <jats:italic>tert\u2010<\/jats:italic>butyl groups provided the novel steroidal \u03b4\u2010amino acid <jats:bold>9\u2009a<\/jats:bold> and the \u03b4\u2010amino acid derivatives <jats:bold>9\u2009b<\/jats:bold>,\u2009<jats:bold>c<\/jats:bold> in good yields (76\u201386\u2009%).<\/jats:p>","DOI":"10.1002\/chem.200601076","type":"journal-article","created":{"date-parts":[[2006,9,22]],"date-time":"2006-09-22T05:29:28Z","timestamp":1158902968000},"page":"8336-8344","source":"Crossref","is-referenced-by-count":17,"title":["An Efficient Access to Novel Enantiomerically Pure Steroidal \u03b4\u2010Amino Acids"],"prefix":"10.1002","volume":"12","author":[{"given":"Hans Wolf","family":"S\u00fcnnemann","sequence":"first","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Anja","family":"Hofmeister","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"J\u00f6rg","family":"Magull","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Armin","family":"de Meijere","sequence":"additional","affiliation":[],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2006,10,27]]},"reference":[{"key":"e_1_2_6_1_2","doi-asserted-by":"publisher","DOI":"10.1002\/ejoc.200500386"},{"key":"e_1_2_6_2_2","unstructured":"\u00a0"},{"key":"e_1_2_6_3_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19941061705"},{"key":"e_1_2_6_3_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.199416991"},{"key":"e_1_2_6_4_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.19931050905"},{"key":"e_1_2_6_4_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.199312441"},{"key":"e_1_2_6_5_2","unstructured":"\u00a0"},{"key":"e_1_2_6_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/S1381-1177(00)00107-7"},{"key":"e_1_2_6_7_2","doi-asserted-by":"publisher","DOI":"10.1002\/(SICI)1097-0282(1999)51:5<343::AID-BIP4>3.0.CO;2-W"},{"key":"e_1_2_6_8_2","doi-asserted-by":"publisher","DOI":"10.1007\/978-94-010-0464-0_264"},{"key":"e_1_2_6_9_2","unstructured":"\u00a0"},{"key":"e_1_2_6_10_2","doi-asserted-by":"publisher","DOI":"10.2174\/1385272054553631"},{"key":"e_1_2_6_11_2","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3757(20010601)113:11<2137::AID-ANGE2137>3.0.CO;2-O"},{"key":"e_1_2_6_11_3","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3773(20010601)40:11<2076::AID-ANIE2076>3.0.CO;2-G"},{"key":"e_1_2_6_12_2","unstructured":"\u00a0"},{"key":"e_1_2_6_13_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo971415e"},{"key":"e_1_2_6_14_2","doi-asserted-by":"publisher","DOI":"10.1021\/ja9814671"},{"key":"e_1_2_6_15_2","doi-asserted-by":"publisher","DOI":"10.1002\/hlca.19980810514"},{"key":"e_1_2_6_16_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo049535r"},{"key":"e_1_2_6_17_2","doi-asserted-by":"publisher","DOI":"10.1016\/S0040-4020(99)00541-4"},{"key":"e_1_2_6_18_2","unstructured":"\u00a0"},{"key":"e_1_2_6_19_2","doi-asserted-by":"publisher","DOI":"10.1002\/1521-3765(20010917)7:18<4035::AID-CHEM4035>3.0.CO;2-P"},{"key":"e_1_2_6_20_2","doi-asserted-by":"publisher","DOI":"10.1002\/ange.200352162"},{"key":"e_1_2_6_20_3","doi-asserted-by":"publisher","DOI":"10.1002\/anie.200352162"},{"key":"e_1_2_6_21_2","unstructured":"The bromoenol triflates were assembled from theN\u2010substituted 4\u2010piperidones to the corresponding trimethylsilyl enol ethers via the \u03b1\u2010bromopiperidinones1\u2009a\u2013cusing very economical conditions based on trifluoromethanesulfonic acid anhydride and triethylamine:"},{"key":"e_1_2_6_22_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo9522771"},{"key":"e_1_2_6_23_2","doi-asserted-by":"publisher","DOI":"10.1021\/jm980204e"},{"key":"e_1_2_6_24_2","doi-asserted-by":"publisher","DOI":"10.1021\/ol016054a"},{"key":"e_1_2_6_25_2","doi-asserted-by":"publisher","DOI":"10.1021\/jo00028a066"},{"key":"e_1_2_6_26_2","doi-asserted-by":"publisher","DOI":"10.1055\/s-1993-25931"},{"key":"e_1_2_6_27_2","unstructured":"The use of different amide bases such as NaHMDS or LiHMDS for an improved regioselectivity during the enolate formation in \u03b1\u2010bromopiperidinone1\u2009b cled to complete decomposition of the substrates."},{"key":"e_1_2_6_28_2","unstructured":"CCDC\u2010605\u2009599 (2\u2009b) contains the supplementary crystallographic data for compound2\u2009b. 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