Reaction of the N-(α-chloroalkyloxycarbonyl)pyrrolidines 1 with lithium powder and a catalytic amount of 4,4′-di-tert-butylbiphenyl (DTBB, 2.5 mol-%) in the presence of different electrophiles [iBuCHO, tBuCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe, Ph2CO, Me3SiCl], in THF at temperatures ranging between –78 and –60°C leads, after hydrolysis with water, to the expected functionalized carbamates 2. Deprotection
Diastereoselectivity of the mercuration of acyclic allylic alcohols
作者:Bernd Giese、Dieter Bartmann
DOI:10.1016/s0040-4039(00)98432-6
日期:1985.1
The diastereoselectivity of the mercuration of acyclic alkenes can be reversed by changing the substituent in the allylic position; with alcohols the erythro isomers and with esters or hemiacetals the threo isomers and are formed predominantly (Table I).
Redox-Triggered CC Coupling of Diols and Alkynes: Synthesis of β,γ-Unsaturated α-Hydroxyketones and Furans by Ruthenium-Catalyzed Hydrohydroxyalkylation
作者:Emma L. McInturff、Khoa D. Nguyen、Michael J. Krische
DOI:10.1002/anie.201311130
日期:2014.3.17
ruthenium‐catalyzed CCcoupling of alkynes and vicinal diols to form β,γ‐unsaturated ketones occurs with complete levels of regioselectivity and good to complete control over the alkene geometry. Exposure of the reaction products to substoichiometric quantities of p‐toluenesulfonic acid induces cyclodehydration to form tetrasubstituted furans. These alkyne‐diolhydrohydroxyalkylations contribute to a
Study of the regio- and enantioselectivity of the reactions of osmium tetroxide with allylic alcohols and allylic sulfonamides
作者:Daqiang Xu、Christine Y. Park、K.Barry Sharpless
DOI:10.1016/s0040-4039(00)77153-x
日期:1994.4
geranyl sulfonamides suggest the presence of a moderate attractive interaction between OsO4 and the allylic groups bearing acidic protons. This allylic directing effect may be due to the development of a hydrogen bonding interaction between OsO4 and the substrates during the osmylation process. The potential for a hydrogen bond can also have a substantial effect on the enantioselectivities of the osmium