53366-57-7Relevant academic research and scientific papers
Direct Cross-Coupling of Allylic C(sp3)?H Bonds with Aryl- and Vinylbromides by Combined Nickel and Visible-Light Catalysis
Huang, Long,Rueping, Magnus
supporting information, p. 10333 - 10337 (2018/07/31)
An efficient protocol for the direct allylic C(sp3)?H bond activation of unactivated tri- and tetrasubstituted alkenes and their functionalization with aryl- and vinylbromides by nickel and visible-light photocatalysis has been developed. The method allows C(sp2)?C(sp3) formation under mild reaction conditions with good functional-group tolerance and excellent regioselectivity.
Rearrangement in Stereoretentive Syntheses of Menthyl Chloride from Menthol: Insight into Competing Reaction Pathways through Component Quantification Analysis
Hintermann, Lukas,Wong, Kit Ming
supporting information, p. 5527 - 5536 (2017/10/06)
The enantiopure reagent menthyl chloride (2) is generally prepared from (–)-(1R)-menthol (1) with Lucas' reagent (ZnCl2 in conc. aqueous HCl) in a stereoretentive reaction that appeared to be free from accompanying rearrangements. The same was assumed for a recent synthesis of 2 through TiCl4-catalyzed extrusion of SO2 from menthyl chlorosulfite (3). The products of both syntheses have now been analyzed by quantitative 1H and 13C NMR methods, and all reaction components have been identified down to the ≤ 0.5 mol-% level. Either reaction is accompanied by cationic rearrangement to the considerable extent of 18–25 mol-%. Besides the expected 2, neomenthylchloride (4) and five rearrangement products have been identified, among them three regioisomeric tertiary chloromenthanes (9, 10, 11), and both a secondary (12) and tertiary chloride (16) derived from ψ-menthane (1-isobutyl-3-methylcyclopentane). A scheme of rearrangement pathways starting from a common menthyl carbenium ion pair is derived. The effect of purification protocols on crude 2 has been studied quantitatively. Either selective solvolysis of tertiary sideproducts (98 mol-% purity) or low-temperature crystallization (≥ 97 mol-% purity) was successful. An improved, scalable synthesis of 2 through the catalytic rearrangement of chlorosulfite 3 is reported.
Cyclizations of ω-Allenyl Radicals
Apparu, Marcel,Crandall, Jack K.
, p. 2125 - 2130 (2007/10/02)
Allenyl halides of structure (CH3)2C=C=CH(CH2)nX with n=3-6 have been prepared and reacted with n-Bu3SnH to generate the corresponding radicals for examination of the cyclization reactions of these reactive intermediates.The observed hydrocarbon products indicate that cyclization occurs for the n=3,4, and 5 radicals but not for the n=6 species.The n=3 radical isomerizes very efficiently by intramolecular addition to the sp carbon of the allene group.The n=5 intermediate reacts relatively slowly by attack at the near sp2 carbon.Both cyclization modes are observed for the n=4 species.The details of these radical cyclizations are discussed.
