N-H Insertion Reactions Catalyzed by a Dirhodium Metal-Organic Cage: A Facile and Recyclable Approach for C-N Bond Formation
作者:Jian Kang、Lianfen Chen、Hao Cui、Li Zhang、Cheng-Yong Su
DOI:10.1002/cjoc.201600818
日期:2017.6
Rh‐Rh bonds [Rh4(pbeddb)4(H2O)2(DMAC)2] (MOC‐18; pbeddb2− = 3,3'‐(1,3‐phenylenebis(ethyne‐2,1‐diyl))dibenzoate) was applied to the N—H insertion reactions with diazo compounds. This method offered an environmentally friendly and highly efficient approach for C—Nbondformation.
Blue light-promoted N–H insertion of amides, isatins, sulfonamides and imides into aryldiazoacetates: Synthesis of unnatural α-aryl amino acid derivatives
作者:Celso Y. Okada、Caio Y. dos Santos、Igor D. Jurberg
DOI:10.1016/j.tet.2020.131316
日期:2020.12
A photochemical protocol using blue light allows the N–H insertion of amides, isatins, sulfonamides and imides into aryldiazoacetates to afford the corresponding α-amino esters. This method is experimentally simple, inexpensive and tolerates numerous functional groups, thus allowing the straightforward preparation of a variety of α-aryl amino acid derivatives in good yields.
Indirect electrochemical methoxylation of -acyl and -carboalkoxy α-aminoacidesters in α-position to nitrogen is possible, if chloride is used as mediator. The course of the reaction depends upon the protecting group as well as upon the amino acid side-chain. Increased electron withdrawing effects of the protecting group are accelerating the reaction. On the other hand aliphatic side-chains are diminishing
Formation of Non-Natural α,α-Disubstituted Amino Esters via Catalytic Michael Addition
作者:Kip A. Teegardin、Lacey Gotcher、Jimmie D. Weaver
DOI:10.1021/acs.orglett.8b03161
日期:2018.11.16
of amino esters is explored, and the first catalytic Michaeladdition of α-amino esters is demonstrated. These studies indicate that the acidity of the αC–H is the primary factor determining reactivity. Thus, polyfluorophenylglycine amino esters yield novel α-amino esters in the presence of a catalytic amount of a guanidine-derived base and Michael acceptors. Reactivity requires an acidic N–H, which
The transfer of chirality from optically active propargyl and cinnamyl N-acyl-C-phenylglycinates to α-branched ketones may be achieved by sigmatropicrearrangements of oxazole Intermediates followed by catalytic hydrogenation of the resulting 3-oxazolinones and subsequent reductive ring cleavage. From ()-4-phenyl-3-buten-1-ol both enantiomers of 1,4-diphenyl-2-methylbutan-1-one (6) could be obtained