Synthesis of the Cores of Hypocrellin and Shiraiachrome: Diastereoselective 1,8-Diketone Aldol Cyclization
摘要:
Intramolecular 1,8-diketone aldol reactions Were Studied as a tool for the construction of the seven-membered rings of hypocrellin and shiraiachrome. Conditions were identified to obtain the relative stereochemistries present in the two natural products with excellent diastereoselectivity. In addition, a nine-membered ring congener, which has yet to be observed in nature, formed with high selectivity when a hindered amine was used in conjunction with silazide bases.
Palladium catalyzed coupling reactions of diiodoarenes with allylic and homoallylic alcohols
摘要:
A sequential transformation consisting of a twofold Heck reaction of 1,2-diiodobenzene (14) with allyl alcohol (2) followed by an intramolecular aldol condensation is suitable for the construction of the benzocyclohept-2-ene-2-carboxaldehyde (15). Under the same reaction conditions 1,8-diiodonayhthalene (7) lends to 1-acenaphthenyl-methanol (6), 2-(1-acenaphthenyl)-ethanol (8), 1-(1w-acenaphthenyl)-ethanol (11), 5-(1,8-naphthalena)-nonan-2,8-dione (12) and 5-(1-naphthyl)-3-methylpentan-2-on (13) mainly.
Calix[4]pyrroles with Shortest Possible Strap: Exclusively Selective toward Fluoride Ion
作者:Ritwik Samanta、B. Sathish Kumar、Pradeepta K. Panda
DOI:10.1021/acs.orglett.5b01866
日期:2015.9.4
Four new calix[4]pyrroles with the shortest possible strap so far through ortho-linking of the aromatic unit have been synthesized, including a naphthalene-derived fluorescent receptor. They show exclusive selectivity toward the fluoride ion as confirmed by H-1 NMR, isothermal titration calorimetry, and fluorescence spectroscopic study. Anion affinity could also be modulated further via functionalization at the strap. Computational analysis displays calix[4]pyrroles binding to fluoride ion in a very unusual 1,3-alternate conformation where the anion resides on the opposite side of the strap.
Palladium catalyzed coupling reactions of diiodoarenes with allylic and homoallylic alcohols
A sequential transformation consisting of a twofold Heck reaction of 1,2-diiodobenzene (14) with allyl alcohol (2) followed by an intramolecular aldol condensation is suitable for the construction of the benzocyclohept-2-ene-2-carboxaldehyde (15). Under the same reaction conditions 1,8-diiodonayhthalene (7) lends to 1-acenaphthenyl-methanol (6), 2-(1-acenaphthenyl)-ethanol (8), 1-(1w-acenaphthenyl)-ethanol (11), 5-(1,8-naphthalena)-nonan-2,8-dione (12) and 5-(1-naphthyl)-3-methylpentan-2-on (13) mainly.
Synthesis of the Cores of Hypocrellin and Shiraiachrome: Diastereoselective 1,8-Diketone Aldol Cyclization
作者:Erin M. O’Brien、Jingxian Li、Patrick J. Carroll、Marisa C. Kozlowski
DOI:10.1021/jo9018914
日期:2010.1.1
Intramolecular 1,8-diketone aldol reactions Were Studied as a tool for the construction of the seven-membered rings of hypocrellin and shiraiachrome. Conditions were identified to obtain the relative stereochemistries present in the two natural products with excellent diastereoselectivity. In addition, a nine-membered ring congener, which has yet to be observed in nature, formed with high selectivity when a hindered amine was used in conjunction with silazide bases.