Diastereofacial selectivity in 1,3-dipolar cycloadditions. Reactions of diazomethane with endo,cis-5,6-disubstituted bicyclo[2.2.2]oct-2-enes.
摘要:
The reaction of diazomethane with endo,cis-5,6-diacetoxy, dimesyloxy, bis(methoxycarbonyl) and dihydroxybicyclo[2.2.2]oct-2-ene derivatives, respectively, afforded either only the anti adduct or a mixture of anti and syn adducts wherein the anti diasteroisomer was highly dominant (greater-than-or-equal-to 10:1). The observed facial selectivity provides convincing evidence that direct through space interactions between the attacking 1,3-dipole and acetoxy, hydroxy etc. substituents are, as a whole, repulsive. Steric ''non-bonded'' repulsions and dipole-dipole interactions override possible stabilizing interactions, e.g. orbital interactions and hydrogen bonding effects.
Hybrid bidentate ligand for functional recognition: an application to regioselective CC double bond hydrogenation
作者:Frédéric Goettmann、Pascal Le Floch、Clément Sanchez
DOI:10.1039/b600127k
日期:——
Regioselectivity increases in CC double bond hydrogenation could be obtained for Lewis basic substrates on a Lewis acidic support by using a rhodium complex supported on a mesoporous solid.
BOUCHER, JEAN-LUC;STELLA, LUCIEN, TETRAHEDRON, 44,(1988) N 12, C. 3607-3615
作者:BOUCHER, JEAN-LUC、STELLA, LUCIEN
DOI:——
日期:——
Photoinduced Intramolecular Cyclopentanation vs Photoprotolytic Oxametathesis in Polycyclic Alkenes Outfitted with Conformationally Constrained Aroylmethyl Chromophores
作者:Roman A. Valiulin、Teresa M. Arisco、Andrei G. Kutateladze
DOI:10.1021/jo301909j
日期:2013.3.1
Intramolecular photoinduced cyclizations are investigated in photoprecursors assembled in a modular fashion via a Diels–Alderreaction of acetylenic dienophiles with subsequent Michael additions of aromatic ketones to install a chromophore capable of initiating Paternò–Büchi cycloadditions or radical cyclization cascades. The protolytic oxametathesis in these systems allows for rapidaccess to novel
Diastereofacial selectivity in 1,3-dipolar cycloadditions. Reactions of diazomethane with endo,cis-5,6-disubstituted bicyclo[2.2.2]oct-2-enes.
作者:Marina Burdisso、Remo Gandolfi
DOI:10.1016/s0040-4020(01)88294-6
日期:1991.9
The reaction of diazomethane with endo,cis-5,6-diacetoxy, dimesyloxy, bis(methoxycarbonyl) and dihydroxybicyclo[2.2.2]oct-2-ene derivatives, respectively, afforded either only the anti adduct or a mixture of anti and syn adducts wherein the anti diasteroisomer was highly dominant (greater-than-or-equal-to 10:1). The observed facial selectivity provides convincing evidence that direct through space interactions between the attacking 1,3-dipole and acetoxy, hydroxy etc. substituents are, as a whole, repulsive. Steric ''non-bonded'' repulsions and dipole-dipole interactions override possible stabilizing interactions, e.g. orbital interactions and hydrogen bonding effects.