Tertiary and Quaternary Carbon Formation via Gallium-Catalyzed Nucleophilic Addition of Organoboronates to Cyclopropanes
作者:Truong N. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.7b03349
日期:2018.1.5
via homoconjugate addition of organoboron nucleophiles to diester- and ketone-functionalized cyclopropanes. Electron donor group cyclopropane substituents were not needed, allowing electron-deficient aryl, alkenyl, alkyl, and hydrogen-substituted cyclopropanes to be used. The catalytic conditions were compatible with alkenyl, alkynyl, and arylnucleophiles, including ortho-substituted aromatics, to
Lewis Acid Mediated (3 + 2) Cycloadditions of Donor–Acceptor Cyclopropanes with Heterocumulenes
作者:Alexander F. G. Goldberg、Nicholas R. O’Connor、Robert A. Craig、Brian M. Stoltz
DOI:10.1021/ol302494n
日期:2012.10.19
Isocyanates, isothiocyanates, and carbodiimides are effective substrates in (3 + 2) cycloadditions with donor–acceptor cyclopropanes for the synthesis of five-membered heterocycles. These reactions exhibit a broad substrate scope, high yields, and well-defined chemoselectivity. Discussed herein are the implications of Lewis acid choice on the stereochemical outcome and the reaction mechanism.
Design, Preparation, X-ray Crystal Structure, and Reactivity of <i>o</i>-Alkoxyphenyliodonium Bis(methoxycarbonyl)methanide, a Highly Soluble Carbene Precursor
作者:Chenjie Zhu、Akira Yoshimura、Lei Ji、Yunyang Wei、Victor N. Nemykin、Viktor V. Zhdankin
DOI:10.1021/ol301268j
日期:2012.6.15
The preparation, X-ray structure, and reactivity of new, highly soluble, and reactive iodonium ylides derived from malonate methyl ester and bearing an ortho substituent on the phenyl ring are reported. These new reagents show higher reactivity than common phenyliodonium ylides in the Rh-catalyzed cyclopropanation, C–H insertion, and transylidation reactions under homogeneous conditions.
Radical Cyclizations for the Synthesis of Pyrroloindoles: Progress toward the Flinderoles
作者:Joanne E. Curiel Tejeda、Bryan K. Landschoot、Michael A. Kerr
DOI:10.1021/acs.orglett.6b00768
日期:2016.5.6
Under the influence of Lewis acid catalysis, donor/acceptor cyclopropanes underwent nucleophilic ring opening by indolines. The resulting N-alkyl indolines bearing a pendant malonyl moiety oxidatively cyclized to 1,2-pyrroloindoles. This method was showcased by the preparation of the skeletal structure of the flinderoles.
RhII-Catalyzed Thermal Cyclopropanations of a Phenyliodonium Bis(carbomethoxy)methylide with Alkenes and Dienes
作者:Georgia Georgakopoulou、Christos Kalogiros、Lazaros P. Hadjiarapoglou
DOI:10.1055/s-2001-18750
日期:——
Iodonium ylide 2, derived from dimethyl malonate, undergoes facile thermal cycloaddition with alkenes and dienes catalyzed with Rh2(OAc)4 to form the corresponding cyclopropanedicarboxylates and vinylcyclopropanedicarboxylates, respectively, in excellent yields.