Branched α-amino acids incorporating an alkynyl group have been prepared by copper-catalysed reaction of a serine-derived organozinc reagent with bromoallenes. Substantial improvements to our previously reported Negishi cross-coupling of the serine-derived organozinc reagent with cycloalkenyl triflates are possible using a combination of LiCl and SPhos as ligand. Finally, we report a preliminary example
Catalytic Multisite-Selective Acetoxylation Reactions at sp<sup>2</sup> vs sp<sup>3</sup> C–H Bonds in Cyclic Olefins
作者:Zhong-Lin Zang、Sheng Zhao、Shuklachary Karnakanti、Cheng-Lin Liu、Pan-Lin Shao、Yun He
DOI:10.1021/acs.orglett.6b02458
日期:2016.10.7
The first Pd-catalyzed multisite-selective acetoxylation reactions are disclosed at an unactivated alkene sp2 C–H bond versus secondary allylic sp3 C–H bond in cyclic olefins via the modulation of directing groups. The different directing groups overcome the key challenge in differentiating C–H bonds and provide a new controlling approach for site-specific C–H activation. A wide variety of substrates
New routes to β-cycloalkylalanine derivatives using serine-derived organozinc reagents
作者:Tomas Carrillo-Marquez、Lorenzo Caggiano、Richard F. W. Jackson、Urszula Grabowska、Alastair Rae、Matthew J. Tozer
DOI:10.1039/b512784j
日期:——
latter route allows access to a range of cycloalkyl derivatives, with ring sizes of 5-8. beta-(1-Methyl-1-cyclohexyl)alanine may be prepared using reaction of the zinc-copper reagent 2 with 3-methyl-2-cyclohexenyl chloride, followed by hydrogenation. The corresponding cyclopentyl derivative may be prepared by reaction of the same zinc-copper reagent 2 with diethyl geranylphosphate, followed by ring-closing