79287-72-2Relevant academic research and scientific papers
Phosphine-catalyzed stereoselective tandem annulation reaction for the synthesis of chromeno[4,3- b]pyrroles
Dai, Zonghao,Zhu, Jin,Su, Wenbo,Zeng, Wuxian,Liu, Ziqi,Chen, Ming,Zhou, Qingfa
, p. 7008 - 7012 (2020)
A phosphine-catalyzed tandem cyclization reaction has been developed to provide a series of chromeno[4,3-b]pyrrole derivatives, which contain three consecutive asymmetric centers. The reaction has a good yield, excellent stereoselectivity, and Z/E selectivity. The new method is simple, requires only mild conditions, and shows tolerance for various functional groups. Similarly, this reaction can be catalyzed by a chiral phosphine catalyst to achieve asymmetric synthesis.
Cross coupling of sulfonyl radicals with silver-based carbenes: A simple approach to β-carbonyl arylsulfones
Li, Jingjing,Lian, Pengcheng,Wan, Xiaobing,Wang, Hanghang,Zheng, Yonggao
supporting information, p. 2163 - 2169 (2020/03/27)
A coupling reaction between sulfonyl radicals and silver-based carbenes has been well established. This simple radical-carbene coupling (RCC) process provided an efficient approach to a variety of β-carbonyl arylsulfones from sodium arylsulfinates and diazo compounds, and was characterized by wide substrate scope, easy scale-up, simple manipulation, accessible starting materials, and mild reaction conditions.
Fast Living Polymerization and Helix-Sense-Selective Polymerization of Diazoacetates Using Air-Stable Palladium(II) Catalysts
Chu, Jia-Hong,Xu, Xun-Hui,Kang, Shu-Ming,Liu, Na,Wu, Zong-Quan
supporting information, p. 17773 - 17781 (2019/01/04)
In this work, air-stable palladium(II) catalysts bearing bidentate phosphine ligands were designed and prepared, which could initiate fast and living polymerizations of various diazoacetate monomers under mild conditions. The polymerization afforded the desired polymers in high yields with controlled molecular weights (Mns) and narrow molecular weight distributions (Mw/Mns). The Mns of the isolated polymers were linearly correlated to the initial feed ratios of monomer to catalyst, confirming the living/controlled manner of the polymerizations. The Mn also increased linearly with the monomer conversion, and all of the isolated polymers showed narrow Mw/Mns. The polymerization was relatively fast and could be accomplished within several minutes. Such fast living polymerization method can be applied to a wide range of diazoacetate monomers in various organic solvents at room temperature in air. Taking advantage of the living nature, we facilely prepared a series of block copolymers through chain extension reactions. The amphiphilic block copolymers synthesized by this method exhibited interesting self-assembly properties. Moreover, polymerization of achiral bulky diazoacetate by Pd(II) catalysts bearing a chiral bidentate phosphine ligand leads to the formation of polymers with high optical activity due to the formation of the predominantly one-handed helix of the main chain. The helix sense of the polymers was determined by the chirality of the Pd(II) catalysts.
Phosphine-Catalyzed Domino β/γ-Additions of Benzofuranones with Allenoates: A Method for Unsymmetrical 3,3-Disubstituted Benzofuranones
Huang, Zhusheng,Yang, Xiuqin,Yang, Fulai,Lu, Tao,Zhou, Qingfa
supporting information, p. 3524 - 3527 (2017/07/17)
A phosphine-catalyzed domino process of benzofuranones with allenoates has been developed which furnishes highly functionalized unsymmetrical 3,3-disubstituted benzofuranones in synthetically useful yields. The mechanism for the transformation is a tandem β-umpolung/γ-umpolung process.
A convenient route to higher sugars by two-carbon chain elongation using Wittig/dihydroxylation reactions
Jorgensen,Iversen,Madsen
, p. 4625 - 4629 (2007/10/03)
The combination of a Wittig olefination and a dihydroxylation reaction constitutes a facile synthetic protocol for the transformation of unprotected carbohydrates into higher sugars. The Wittig reaction is carried out with tert-butyl or diphenylmethyl ester stabilized phosphoranes to give (E)-configured α,β-unsaturated esters as the only products in most cases. These are dihydroxylated in a diastereoselective fashion using OsO4/NMO. The stereochemical outcome in the dihydroxylation follows Kishi's empirical rule and gives high diastereoselectivity (5:1-8:1) when starting from sugars with the 2,3-threo configuration. When starting from sugars with the 2,3-erythro configuration, the diastereoselectivity in the dihydroxylation is low (2:1-2.5:1). As a result, the Wittig/dihydroxylation protocol is most effective for producing higher sugars with the galacto configuration at the reducing end. The two steps can either be carried out individually or, more efficiently, as a one-pot procedure.
Efficient and practical synthesis of 1β-methylcarbapenems
Kume, Masaharu,Ooka, Hiroaki,Ishitobi, Hiroyuki
, p. 1635 - 1646 (2007/10/03)
An efficient and practical method of synthesizing 1β-methylcarbapenem, S-4661, was developed. (4R)-4-[(1S)-1-Methylallyl]-2-azetidinone 2, prepared stereoselectively from commercially available acetoxy-azetidinone 3, was converted to the β-keto ester 6 in four steps. The iodonium ylide 5 was prepared from 6, then cyclized to obtain the bicyclic β-keto ester 4. Finally, 4 was processed to the target product, S-4661, by conventional procedures.
Wittig chain extension of unprotected carbohydrates: Formation of carbohydrate-derived α,β-unsaturated esters
Railton, Craig J.,Clive, Derrick L.J.
, p. 69 - 77 (2007/10/03)
Unprotected carbohydrates react with Wittig reagents 6 and 7 to give unsaturated esters. This homologation has been used to prepare an intermediate (18) previously employed in a synthesis of Kdo (19).
