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
Carbonyl Allenylations andPropargylations by 3-Chloro-1-propyne or 2-Propynyl Mesylateswith Tin(IV) Chloride and Tetrabutylammonium Iodide
作者:Yoshiro Masuyama、Akiko Watabe、Yasuhiko Kurusu
DOI:10.1055/s-2003-41012
日期:——
By the use of tin(IV) chloride and tetrabutylammonium iodidein dichloromethane, 3-chloro-1-propyne or 2-propynyl mesylate canbe applied to allenylation and propargylation of aldehydes (carbonylallenylation and propargylation) to produce a mixture of 1-substituted2,3-butadien-1-ols and 1-substituted 3-butyn-1-ols. 1-Substituted2-propynyl mesylates selectively cause carbonyl propargylation,while 3-substituted 2-propynyl mesylates cause carbonyl allenylation.
Regioselective Propargylation of Aldehydes and Ketones by Electrochemical Reaction using Zinc and Aluminum Anodes
作者:Nobuhito Kurono、Kazuya Sugita、Masao Tokuda
DOI:10.1016/s0040-4020(99)01089-3
日期:2000.2
Electrochemical propargylation of aldehydes and ketones with unsubstituted or α-substituted propargylic bromides using platinum cathode and zinc anode proceeded efficiently under mild conditions to give the corresponding homopropargyl alcohols exclusively in high yields. Similar electrochemical propargylation with γ-substituted propargyl bromides gave the corresponding homoallenyl alcohols as major
Synthese de composes dihydro-2,3 furanniques par hydroboration d'alcools β-acetyleniques
作者:Gilbert Dana、Bruno Figadère、Estera Touboul
DOI:10.1016/s0040-4039(01)80919-9
日期:1985.1
Hydroboration of β-acetylenic alcohols followed by NaOH/H2O2 oxidation leads to hemiacetals of γ-aldols which are easily dehydrated to 2,3-dihydrofuran compounds. The reaction gives good yields with hindered alcohols and its stereochemistry may be controlled during the organometallic synthesis of the starting alcohol.
β-炔醇的硼氢化反应,然后进行NaOH / H 2 O 2氧化,导致生成的γ-醛缩醛半缩醛容易脱水成2,3-二氢呋喃化合物。该反应在受阻醇的作用下具有良好的收率,并且可以在起始醇的有机金属合成过程中控制其立体化学。
<i>Ortho-</i>[2,3]-Wittig Rearrangement of Benzyl Propargyl Ethers: Striking Preference over the Competing [1,2]-Wittig Shift
Treatment of benzyl γ-(trimethylsilyl)propargyl ether with n-BuLi is shown to afford the rarely precedent ortho-[2,3]-Wittig product in remarkable preference to the [1,2]-Wittig product. The factors governing the periselectivity in this type of carbanion rearrangement are discussed.