New Annulations via Platinum-Catalyzed Enyne Cyclization and Cyclopropane Cleavage
作者:Cristina Nevado、Catalina Ferrer、Antonio M. Echavarren
DOI:10.1021/ol0486573
日期:2004.9.1
[reaction: see text] Oxidative ringopening of 3-oxabicyclo[4.1.0]hept-4-enes, formed by the intramolecular Pt(II)-catalyzed cyclopropanation of enol ethers by alkynes, gives oxepane derivatives. Alternatively, the acid-catalyzedopening of the cyclopropane ring leads to dihydrobenzofurans or 3,4-dihydro-2H-chromenes.
Highly diastereoselective hydrosilylations of allylic alcohols
作者:Mark G. McLaughlin、Matthew J. Cook
DOI:10.1039/c4cc00138a
日期:——
The highly syn-selective hydrosilylation of allylic alcohols was developed which, following oxidation, provided 1,3 alcohols containing two contiguous stereocentres.
Studies on the stereoselective hydroboration of vinyl ethers
作者:Glenn J. McGarvey、Joginder S. Bajwa
DOI:10.1016/s0040-4039(01)84582-2
日期:——
The diastereoselective hydroboration/oxidation of several asymmetric vinylethers is presented.
提出了几种不对称乙烯基醚的非对映选择性硼氢化/氧化。
Regioselectivity and Stereospecificity in a Contrastereoelectronically Controlled Pinacol Rearrangement of Alkoxycyclobutane Derivatives. A Novel Route to Vicinally Substituted Cyclopentanones
作者:Debasis Patra、Subrata Ghosh
DOI:10.1021/jo00113a036
日期:1995.4
A four-step sequence for the synthesis of vicinally substituted cyclopentanones 5 and 9 has been developed starting from the acyclic ketones 1. The key step involves a stereospecific pinacol-type rearrangement of the cyclobutane ring embodied in oxabicyclo[3.2.0]-heptanes 4 and 8 involving exclusive migration of the stereoelectronically disfavored cyclobutane bond. The oxabicyclo[3.2.0]heptanes have been obtained by copper(I) triflate (CuOTf) catalyzed intramolecular photocycloaddition of the dienes 3 prepared from the ketones 1 on reaction with (ethoxyvinyl)lithium followed by allylation of the carbinols 2. The regioselectivity observed in bond migration has been attributed to be the result of the stabilization of the cation 15 by the neighboring hydroxyl group that is generated during the rearrangement.
Polysubstituted dihydropyrans via the enolate Claisen rearrangement. A stereocontrolled route to C-pyranosides
作者:Steven D. Burke、David M. Armistead、Frank J. Schoenen