Formic acid as a hydride donor: Reduction of acid chlorides to aldehydes

Shamsuddin, K. M.; Zobairi, Md. Omair; Musharraf, M. A.

doi:10.1016/s0040-4039(98)01815-2

Cited by 15 publications

(4 citation statements)

References 5 publications

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“…3 Neither of these methods were entirely satisfactory. Finally a source of pivalaldehyde as a 75% solution in tert-butanol at a much more reasonable price [100 g = £ 31 (€ 45)] was located.…”

Section: Methodsmentioning

confidence: 95%

Synthetic applications of chiral 1,3-dioxolan-4-ones and 3-acyloxazolidin-5-ones

Aitken¹,

McGill²,

Power³

2006

Arkivoc

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Chiral dioxolanones derived from α-hydroxy acids can act as chiral acyl anion equivalents for addition to ethyl crotonate, nitroalkenes and butenolide. Subsequent flash vacuum pyrolysis results in loss of CO and Bu t CHO to give products. The related N-acyl and N-thioacyl-1,3-oxazolidin-5-ones formed from α-amino acids behave in a quite different way with loss of CO 2 upon pyrolysis leading via N-(thio)acylaziridines to oxazolines and thiazolines. The stereochemistry of these transformations, both relative and absolute, is discussed and a mechanism involving an azomethine carboxylate intermediate is proposed.

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Section: Methodsmentioning

confidence: 95%

Synthetic applications of chiral 1,3-dioxolan-4-ones and 3-acyloxazolidin-5-ones

Aitken¹,

McGill²,

Power³

2006

Arkivoc

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“…The smallest aldo‐halide bifunctional building block is chloroacetaldehyde, which was prepared in industry from vinyl chloride or allyl chloride . Reduction of chloroacetic acid, and chlorination of acetaldehyde have also been investigated, but have not been used yet in practical synthesis. This compound is commercially available as an aqueous solution with different concentrations.…”

Section: Aliphatic Axb3 Smentioning

confidence: 99%

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

Ravichandiran

Lai

2016

The Chemical Record

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Compounds containing oxygen, nitrogen, or sulfur atoms inside the rings are attracting much attention and interest due to their biological importance. In recent years, several methods for the synthesis of such molecules have been reported by using aldo-X bifunctional building blocks (AXB3 s) as substrates; these are a wide class of organic molecules that contain at least two reactive sites, among them, one aldehyde, acetal, or semiacetal group was involved. Because of the multiple reactivities, AXB3 s are widely used in the one-pot synthesis of biologically important heterocycles. This review summarizes the synthesis of important heterocycles by using AXB3 s as pivotal components in establishing multicomponent reactions, tandem reactions, and so forth. In many cases, the established reaction systems with AXB3 s were characterized by some green properties, such as easy access to the substrate, mild and environmentally benign conditions, and wide scope of the substrate.

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“…以商品化的齐墩果酸(1)作为起始原料, 吡啶作为溶剂, 乙酸酐作为乙酰化试剂, 室温下以 95%的产率得到齐墩果酸 3 位羟基乙酰化的产物 2. 在二氯亚砜的作用下将 28 位羧酸转化为酰氯后, 我们尝试了多种将酰氯直接还原为醛基的方法, 例如甲酸和氨水体系 [10] 以及三丁基锡氢 [11] , 但遗憾的是都没有取得成功. 因此, 我们采用了间接的方法, 先将酰氯转化为 Weinreb 酰胺 [12a] 为了得到乙酰氧基化的产物, 我们尝试了多种条件来抑制 β-氢消除, 例如改变溶剂(乙酸 [15] , 甲苯, 叔丁醇 [16] ), 添加剂(2,2,2-三甲基乙酸 [17] ), 氧化剂(乙酸银 [9i] ) 和温度(50 到 90 ℃), 但是反应结果都没有明显改变.…”

Section: O-乙酰基肟和 O-甲基肟作为导向基团的 C-h 活化反应的尝试unclassified

Regio-selective Dehydrogenation on the D or E Rings of Oleanolic Acid by Pd-Promoted C—H Activation

Ma¹,

Li²,

Yu³

2013

Acta Chim. Sinica

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Oleanane-type triterpenes and their glycosides are a structurally and biologically diverse class of metabolites that are widely distributed in terrestrial plants and some marine organisms. Many of these compounds bear functional groups and modifications on the D and/or E rings of the triterpenes. These triterpenes compounds are of growing interest for drug research as they are active constituents of folk medicines and provide valuable pharmacological profiles. For their limited availability and accessibility, chemical synthesis provides a realistic way to determine the availability of homogenous natural products and their derivatives. Here, we report the selective dehydrogenation on the D or E rings of oleanoic acid by palladium promoted C-H activation with 8-aminoquinoline amide (substrate 12) and 2-aminomethylpyridine amide (substrate 16) as the directing groups. Thus, upon treatment with thionyl chloride, the 28-COOH of oleanoic acid was converted into 28-COCl, which coupled with the corresponding amines to provide the substrates readily for dehydrogenation. Notably, treatment of 12 with optimized conditions (1.0 equiv. Pd(OAc) 2 , 1.5 equiv. Oxone ® , 1,2-dichloroethane, 80 ℃, 24 h) led to the dehydrogenated products 13 [double bond at C(15)-C( 16)] and 14 [double bond at C(20)-C(21)] in 55% and 2% yields respectively. Treatment of 16 with optimized conditions (1.0 equiv. Pd(OAc) 2 , 2.0 equiv. Oxone ® , 1,2-dichloroethane, microwave 85 ℃, 50 min) provided 17 [double bond at C(20)-C(21)] and 18 [double bond at C(15)-C( 16)] in 42% and 20% yields respectively. Moreover, the distribution of the products varied in different solvents. It is worth mentioning that the N,N-bidentate ligands (two nitrogen atoms as the coordination sites in 12 and 16) are crucial for the palladium promoted olefination.

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Formic acid as a hydride donor: Reduction of acid chlorides to aldehydes

Cited by 15 publications

References 5 publications

Synthetic applications of chiral 1,3-dioxolan-4-ones and 3-acyloxazolidin-5-ones

Synthetic applications of chiral 1,3-dioxolan-4-ones and 3-acyloxazolidin-5-ones

Aldo‐X Bifunctional Building Blocks for the Synthesis of Heterocycles

Regio-selective Dehydrogenation on the D or E Rings of Oleanolic Acid by Pd-Promoted C—H Activation

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