104281-51-8Relevant articles and documents
New Mild Methodology for the Synthesis of α-Phenylthio and α-Phenylseleno Ketones
Magnus, Philip,Rigollier, Pascal
, p. 6111 - 6114 (2007/10/02)
Treatment of trimethylsilyl enol ethers with the adduct 1, derived from chloramine-T and (PhS)2, gave good yields of α-phenylthioketones.The selenium version of this reagent 2 gave α-phenylselenoketones.
Is pseudorotation the operational pathway for bond shifting within [8]annulenes? Probe of planarization requirements by 1,3-annulation of the cyclooctatetraene ring. Kinetic analysis of racemization and 2-D NMR quantitation of π-Bond alternation and ring inversion as a function of polymethylene chain length
Paquette,Wang,Luo,Cottrell,Clough,Anderson
, p. 239 - 253 (2007/10/02)
The chiral 1,3-bridged cyclooctatetraenes 9a-c have been prepared in nine steps from the appropriate 2-cycloalkenone precursors. Following annulation with ethyl acetoacetate to give 15, trans-1,2-dichloroethylene was cycloadded photochemically in a [2 + 2] reaction and a cyclobutene ring was ultimately formed. Once reduction to alcohol 19 was accomplished, dehydration was effected and the bicyclo[4.2.0]octatrienes so generated underwent disrotatory ring opening to deliver the [8]annulenes. The rates of this electrocyclic ring opening were determined in two examples. Polarimetric studies provided quantitative measure of the readiness with which planar dianion formation occurs as a function of loop size. Unexpectedly, attempts to resolve these molecules failed to deliver them in optically active condition because of too rapid enantiomerization via ring inversion and/or bond shifting. The rates of these processes were determined by 2-D dynamic NMR methods, the data revealing that both processes are accelerated relative to nonbridged models. These and related findings are interpreted in terms of a pseudorotation scheme leading to flattened saddle and not planar-alternate transition states. The unique features associated with this mechanistic phenomenon are discussed.
Synthesis of Cyclic Allylic Sulphides (Ring Sizes 5-15) via Phenylthio Participation
Hannaby, Malcolm,Warren, Stuart
, p. 303 - 311 (2007/10/02)
Dehydration of β-phenylthio alcohols occurs with PhS participation unless stereochemistry prevents it.Without PhS participation, mixtures of allylic and vinylic sulphides are formed, but with PhS participation routes to three families of cyclic allylic su
REARRANGEMENT OF CYCLIC ALCOHOLS WITH AN ADJACENT PHENYLTHIO (PhS-) GROUP: MIGRATION OF A PhS GROUP AROUND A RING.
Hannaby, Malcolm,Warren, Stuart
, p. 765 - 768 (2007/10/02)
PhS migratoin around rings (size 5-15) gives allyl sulphides with a regioselectivity wich varies with ring size.
