The propargyltitanium reagents derived from 1-alkylpropyne condensed with aldehydes to give α-allenyl alcohol regioselectively, while the allenyltitanium reagents generated from 1-alky1-1-butyne derivatives gave threo-β-acetylenic alcohols with high regio- and stereoselectivities. The course of the reaction was determined by the substitution pattern of starting alkynes. The similar reactions of metallated
Novel Isomerically Pure Tetrasubstituted Allylboronates: Stereocontrolled Synthesis of α-Exomethylene γ-Lactones as Aldol-Like Adducts with a Stereogenic Quaternary Carbon Center
作者:Jason W. J. Kennedy、Dennis G. Hall
DOI:10.1021/ja016391e
日期:2002.2.1
1-alkoxycarbonyl vinylcopper(I) intermediates from the conjugate addition of organocuprates onto acetylenic esters were trapped with very high cis-addition selectivity with iodomethylboronic esters in the presence of HMPA. The resulting isomerically pure 3,3-disubstituted allylboronates react with aldehydes in a highly diastereo- and enantioselective manner, providing α-exomethylene γ-lactones with a stereogenic
Reaction of lithium dialkylcuprates with S-2-pyridyl thioates in the presence of oxygen. A carboxylic ester synthesis
作者:Sunggak Kim、Jae In Lee、Bong Young Chung
DOI:10.1039/c39810001231
日期:——
Reaction of lithiumdialkylcuprates with S-2-pyridyl thioates in the presence of oxygen affords carboxylic esters in high yields, whereas under nitrogen it affords ketones.
Mild oxidation of tosylmethylisocyanide to tosylmethylisocyanate: utility in synthetic and medicinal chemistry
作者:Hoang V. Le、Bruce Ganem
DOI:10.1016/j.tetlet.2014.02.016
日期:2014.3
efficient (one-step) oxidation is reported of commercially available tosylmethylisocyanide (TOSMIC) to form tosylmethylisocyanate, making this highly reactive bifunctional molecule a readily available synthetic reagent. Besides engaging in nucleophilic addition reactions with alcohols, amines, and thiols, tosylmethylisocyanate also reacts with carboxylic acids to form tosylmethylamides, which undergo substitution