Reactions of 1-(Benzotriazol-1-yl)-1-phenoxyalkane and (Benzotriazol-1-yl)ethoxyphenylmethane Anions with Nitroarenes: a New Approach to Alkyl and Aryl p-Nitroaryl Ketones
Additions of 1-(.alpha.-alkoxybenzyl)benzotriazoles to enol ethers. New routes to 1,3-diethers
摘要:
1-(alpha-Alkoxybenzyl)benzotriazoles undergo reversible ionization in solution to a benzotriazolyl anion (Bt-) and carboxonium cations PhCH:O+R. These cations can attack the beta-carbon atom of enol ethers to give cation adducts which add the Bt- to form new alpha-(benzotriazol-1-yl)alkyl ethers in which the carbon chains are extended by an alpha-ethoxybenzyl group. Reactions of these adducts with Grignard reagents produce the corresponding 1,3-diethers in high yield. Reduction of the adducts with lithium aluminum hydride gives the corresponding diethers via substitution of the benzotriazolyl moiety with a hydrogen atom or 1-(3-alkoxyalkyl)benzotriazoles via substitution of the alpha-alkoxy group, depending on the reaction conditions and the nature of the adduct.
N-(α-alkoxyalkyl)benzotriazoles are of great importance for biochemical and antitumor activity. A feasible protocol has been developed for the synthesis of N-(α-alkoxyalkyl)benzotriazoles using azoles, aldehydes and alcohols as substrates under electrochemical conditions. The reaction is carried out under acid catalyst- and oxidant-free conditions, so that a variety of synthetically useful nitrogen
Benzotriazole-Mediated Conversions of Aromatic and Heteroaromatic Aldehydes to Functionalized Ketones
作者:Alan R. Katritzky、Hengyuan Lang、Zuoquan Wang、Zhongxing Zhang、Huimin Song
DOI:10.1021/jo00128a039
日期:1995.11
Aromatic and heteroaromatic aldehydes reacted with benzotriazole and triethyl orthoformate in THF to give the corresponding alpha-(benzotriazol-1-yl)aryl ethyl ethers 7 in good yield. The novel acyl anion precursors 7 underwent smooth lithiation at the methine group followed by trapping with alkyl halides, aldehydes, ketones, and imines to yield the expected substituted intermediates of type 9, which were hydrolyzed under mild conditions without isolation. Benzaldehyde, methyl-, chloro-, and methoxy-substituted benzaldehydes, 1-naphthalenecarboxaldehyde, 2- and 3-furaldehydes, 2- and 3-thiophenecarboxaldehydes, and 2-pyridinecarboxaldehyde were all transformed in this manner into a variety of aryl and heteroaryl ketones with alkyl (10), alpha-hydroxyalkyl (12 and 13), alpha-aminoalkyl (14) and acyl(15) substituents.
Synthesis of Acyltrifluoroborates
作者:Aaron M. Dumas、Jeffrey W. Bode
DOI:10.1021/ol300668m
日期:2012.4.20
Acylboranes are among the most elusive boron-containing organic functional groups, a fact that has impeded development of new reactions employing them as substrates. A new synthesis of acyltrifluoroborates from benzotriazole (Bt)-based N,O-acetals has been developed. Two other routes provide acyltrifluoroborates containing alcohols, aldehydes, and carbamates. The ketone-like reactivity of the acyltrifluoroborate functional group is demonstrated, and the first X-ray structure of an acyltrifluoroborate is reported.
Preparation of 1,2- and 1,4-diols via selective cleavage of C-benzotriazole bonds in reductive lithiations of N-(α-alkoxy-benzyl- and -allyl-)benzotriazoles
作者:Alan R. katritzky、Weiliang Bao、Ming Qi、Clara N. Fali、Indra Prakash
DOI:10.1016/s0040-4039(98)01390-2
日期:1998.9
Selective cleavage of C-benzotriazole bonds in the presence of C-O bonds is reported for the reductive lithiation of N-(alpha-alkoxybenzyl)benzotriazoles and N-(alpha-alkoxyallyl)benzotriazoles in a one-step or two-step process. Trapping of the intermediates with carbonyl compounds gave unsymmetrically protected 1,2 or 1,4-diols in moderate yields. (C) 1998 Elsevier Science Ltd. All rights reserved.
Synthesis of β-Alkoxy Ketones and α‘-Functionalized β-Alkoxy Ketones Utilizing Benzotriazole-Stabilized Acyl Anion Synthons
作者:Alan R. Katritzky、Daming Feng、Ming Qi
DOI:10.1021/jo971630v
日期:1998.3.1
1-(alpha-Alkoxyalkyl)benzotriazoles 1a-d add to phenyl vinyl ether to form key intermediates 4a-d, which readily undergo lithiation and subsequent trapping by a variety of electrophiles to give the expected substituted derivatives 7a-d, 9a-c, 11, 13, 15, and 18 in high yields. Subsequent hydrolysis of these compounds provides a novel high-yield acyl anion synthon approach for the synthesis of beta-alkoxy ketones 8 or alpha'-functionalized beta-alkoxy ketones 10, 12, 14, 16, and 19 by short procedures from readily available starting materials.