Dirhodium(II)/Xantphos-Catalyzed Relay Carbene Insertion and Allylic Alkylation Process: Reaction Development and Mechanistic Insights
作者:Bin Lu、Xinyi Liang、Jinyu Zhang、Zijian Wang、Qian Peng、Xiaoming Wang
DOI:10.1021/jacs.1c05701
日期:2021.8.4
with high atom and step economy. Mechanistic studies indicate that the transformation is achieved through a relay dirhodium(II)-catalyzed carbene insertion and allylic alkylation process, in which the catalytic properties of dirhodium are effectively modified by the coordination with Xantphos, leading to good activity in the catalytic allylic alkylation process.
Modification of singlet carbene reactivities by solvent
作者:H. Tomioka、Y. Ozaki、Y. Izawa
DOI:10.1016/s0040-4020(01)96743-2
日期:1985.1
The solventeffect on the reactivity of singlet carbenes has been investigated. Competition reactions between pairs of alcohols for arylcarbenes in various solvents indicates that the O—H insertion selectivity is influenced only by 1,4-dioxane. Thus, phenylcarbene is some 33 times more reactive toward methanol relative to t-butyl alcohol in 90 mol% dioxane than without solvent. Similar competition
A rapid and general access to diversely substituted 5-alkoxyoxazoles 2 (i.e., R1, R2 = alkyl, phenyl) from easily accessible α-triflyloxy/hydroxy esters 1 and nitriles with good yields (41–76%) is reported. The versatility of the cyclization is shown for a range of substrates with high selectivity toward triflates over mesylates and proved to be compatible with sensitive functional groups. As an illustration
A highly efficient catalytic asymmetric Formal [3+2] cycloaddition reaction of 5-alkoxyoxazoles with azodicarboxylate compounds has been realized by a chiral N,N'-dioxide/Co(BF4)2.6H2O complex. A series of poly-substituted 1,2,4-triazolines compounds were obtained...
Toward a Large-Scale Approach to Milnacipran Analogues Using Diazo Compounds in Flow Chemistry
作者:Simon T. R. Müller、Aurélien Murat、Paul Hellier、Thomas Wirth
DOI:10.1021/acs.oprd.5b00308
日期:2016.2.19
The safe use of diazo reagents for the preparation of a key structure in the synthesis of milnacipran analogues is described herein. Using continuous flow technology, the diazo reagent is synthesized, purified, dried, and subsequently used in semi-batch mode for an intramolecular cyclopropanation. Side products formed in the reaction are isolated and rationalized to optimize the process. Different