Synthesis of 1,2-Diheteroatom-Substituted Alkenes via Rhodium-Catalyzed Intramolecular Hydrogen Transfer

Abstract

While 1,2-diheteroatom-substituted alkenes represent useful synthetic building blocks, there are no simple, general procedures available for preparation of such compounds. We describe here a simple catalytic procedure based on rhodium C-H bond activation for the synthesis of diheteroatom alkenes of the type R(3)SiOCH=CHG (G = -OR, -NRR').

Intramolecular hydrogen transfer reactions catalyzed by pentamethylcyclopentadienyl rhodium and cobalt olefin complexes: Mechanistic studies

“…[19] Our mechanistic investigations next looked at this class of substrates by focusing on similar H/D labeling experiments used above. At the outset we envisioned the same two possible mechanisms (Scheme 14, pathways A and B) for the hydrogen transfer reaction with 1,2 diheteroatom substrates.…”

“…In this approach to transfer dehydrogenation, vinyl silane protecting groups are readily installed on the desired substrates and used as hydrogen acceptors. A series of studies in this area has resulted in new base-free, and mild routes to silyl enol ethers [17], 1,2-diheteroatom substituted olefins [18,19], and cyclic enamines. [20] Similar chemistry has been previously reported by Bradley using Cp*M(C 6 H 6 ), M = Co.[21]…”

A Mild Synthesis of New Aryl Vinyl Ethers and Diethyl 1-[(Alkyl)(cyano)methyl]vinylphosphonates via the Substitution of a 2,3-Difunctional Allyl Bromide

“…Functional aryl vinyl ethers have been shown to be promising building blocks in organic synthesis [21–23] as well as important intermediates for the synthesis of a range of products [24–33], new polymeric materials [34–36], and biologically active molecules [37]. Thus, the preparation of these kinds of molecules has always attracted the attention of organic chemists and a growing effort has been directed toward the development of new vinyl ether-based structures and new methods for their construction [38–49].…”

Synergic Transformation of an Ethylenediamine to a Lithium 1,3‐Diaza‐2‐zincacyclopentene via an Alkyllithium/Bis(alkyl)zinc Mixture

“…Noting that the N-CH 2 -CH 2 -N to N-CH=CH-N transformation outlined here for certain will not involve redox processes like that reported by Brookhart et al16 for late transition metal catalysed intramolecular dehydrogenations, in future work we plan to carry out a comprehensive computational study to elucidate the mechanism of this transformation with emphasis on the precise role of the lithium–zinc co-operativity.…”