Medium-Sized Heterocycle Synthesis by the Use of Synergistic Effects of Ni-NHC and γ-Coordination in Cycloisomerization
作者:Chun-Yu Ho、Lisi He
DOI:10.1021/jo5008477
日期:2014.12.19
an NHC–NiH catalyst and γ-heteroatom chelation were used together as a basis for 1,n-diene termini differentiation and for nγ-exo-trig (head-to-tail) product selectivity. Heterocycles bearing an exocyclic methylene such as oxepines, thiepines, siloxepines, and oxocanes were synthesized from the corresponding 1,n-dienes by a fine-tuning of the NHC properties. The implication of the underlying hypothesis
Disclosed is a process for selectively producing (D+1)-member heterocyclic compounds from corresponding unactivated dienes or derivatives thereof in the presence of a transition metal or lanthanide catalyst or a precursor thereof, relative to D-member heterocyclic rings.
A [3 + 3] Annelation Approach to (+)-Rhopaloic Acid B
作者:Julien C. R. Brioche、Katharine M. Goodenough、David J. Whatrup、Joseph P. A. Harrity
DOI:10.1021/ol701553j
日期:2007.9.1
A general and enantiospecific [3 + 3] reaction toward functionalized pyrans is reported that has been employed in the first enantioselective synthesis of (+)-rhopaloic acid B.
Addition of 2-(chloromagnesiomethyl)2-alkenyl ethers to epoxides followed by Pd(0)-catalyzed cyclization: a one-pot synthesis of 3-methylenetetrahydropyrans
作者:Jaap van der Louw、Juul L. van der Baan、Gerardus J.J. Out、Franciscus J.J. de Kanter、Friedrich Bickelhaupt、Gerhard W. Klumpp
DOI:10.1016/s0040-4020(01)92281-1
日期:1992.11
Addition of 2-(chloromagnesiomethyl)-2-propenyl ethers 1a and 1b to epoxides 3 affords ring opening products 6 or 7 which are converted by Pd(0) to 3-methylenetetrahydropyrans 9. Cyclization of the addition products is best effected by a catalyst system generated in situ from Pd(OAc)2 and (i-PrO)3P.
Addition of 2-(phenoxymethyl)-2-propenylmagnesium chloride to epoxides followed by Pd(0)-catalyzed cyclization: A one-pot synthesis of 3-methylenetetrahydropyrans
作者:J. van der Louw、G.J.J. Out、J.L. van der Baan、F.J.J. de Kanter、F. Bickelhaupt、G.W. Klumpp