Enantioselective Synthesis of a Fluorinated Analogue of the Orsellinic Acid-Type Twelve-Membered Lactone Lasiodiplodin
摘要:
The chemoenzymatic synthesis of the racemate and the one enantiomer of the fluorinated analogue 8 of the natural cyclooxygenase inhibitor lasiodiplodin is decribed. A lipase-mediated deracemization of the fluorohydrin 18 provided the chiral, nonracemic building block for the enantioselective synthesis of the title compound. The key step was the formation of the 12-membered lactone by a ring-closing metathesis.
The first palladium-catalyzed Sonogashira coupling of unactivated secondary alkyl bromides
作者:Gereon Altenhoff、Sebastian Würtz、Frank Glorius
DOI:10.1016/j.tetlet.2006.02.111
日期:2006.4
A palladium-carbene catalyzed Sonogashira coupling of unactivated alkylbromides with alkyl substituted alkynes is reported. For the first time, unactivated secondaryalkyl halides were successfully employed in Sonogashirareactions.
New organocopper reagents prepared utilizing highly reactive copper
作者:Reuben D. Rieke、Richard M. Wehmeyer、Tse-Chong Wu、Greg W. Ebert
DOI:10.1016/0040-4020(89)80072-9
日期:1989.1
Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of copper(I) iodide/trialkylphosphine complexes. These activated copper solutions will react with organic halides under very mild conditions to form stable organocopper reagents. Significantly, the organocopper reagents can contain considerable functionalities such as ester, nitrile, chloride, epoxide, and ketone
Synthesis of Functionalized Fullerene by Mono-alkylation of Fullerene Cyclopentadienide
作者:Ryo Hamasaki、Yutaka Matsuo、Eiichi Nakamura
DOI:10.1246/cl.2004.328
日期:2004.3
Mono-alkylation reaction of a fullerene cyclopentadienide with a functionalized alkyl halide quantitatively gave a functionalized [60]fullerenederivative that may bear a variety of functional groups and may exhibit high solubility in various solvents.
Direct formation of functionalized ketones via the coupling of functionalized organocopper reagents with acid chlorides
作者:Richard M. Wehmeyer、Reuben D. Rieke
DOI:10.1016/s0040-4039(00)80534-1
日期:1988.1
reactive copper solutions have been prepared by the lithium naphthalide reduction of a copper(I) iodide/triphenyl-phosphine complex. These copper solutions react rapidly with functionalized alkyl halides to give organocopper reagents which have been effectively trapped with acid chlorides giving functionalized ketones in good yields. Ester, nitrile, chloride, remote epoxide, and, to some degree, ketone groups
作者:Lynda J. Brown、Ian B. Spurr、Stephen C. Kemp、Nicholas P. Camp、Karl R. Gibson、Richard C. D. Brown
DOI:10.1021/ol800767e
日期:2008.6.1
An asymmetrictotalsynthesis of (+)-cis-sylvaticin is described. Key steps include the use of permanganate-mediated oxidativecyclization of 1,5-dienes to synthesize the two major fragments 2 and 3 and a catalytically efficient tethered RCM to unite these THF-containing fragments. In addition, t-BuP 4 base was found to reliably promote rapid alkylation of the butenolide precursor fragment 4.