57483-27-9Relevant articles and documents
One-Pot Synthesis of Cyclopropanes from Methylene Azabicyclo[3.1.0]hexanes Obtained by Formal Sequential [1+2]- and [2+3]-Cycloaddition Reaction of Prop-2-ynylsulfonium Salts and Tosylaminomethyl Enones
Jia, Penghao,Zhang, Qinglong,Zhuge, Yuzhou,Liwei, Xingyue,Huang, You
, p. 438 - 443 (2018)
A formal sequential [1+2]- and [2+3]-annulation of prop-2-ynylsulfonium salts and tosylaminomethyl enones was developed, constructing a series of methylene azabicyclo[3.1.0]hexane derivatives. A one-pot procedure was established via hydration of an enamine intermediate to afford substituted cyclopropanes. Prop-2-ynylsulfonium salts acted as both C2 and C1 synthons in these two processes. (Figure presented.).
Key factors for high diastereo- And enantioselectivity of umpolung cyclizations of aldehyde-containing allylpalladium intermediates
Tsukamoto, Hirokazu,Kawase, Ayumu,Omura, Hirotaka,Doi, Takayuki
supporting information, p. 1743 - 1753 (2019/10/01)
Two palladium/chiral diphosphine-catalyzed umpolung cyc-lizations of aldehyde-containing allylic acetates and allenes with arylboronic acid are fully investigated to establish key factors in their high stereoselectivities. Both cyclization reactions afford cis-disubstituted pyrrolidine and tetrahydrofuran. These occur in high diastereo- and enantioselectivities through a common cationic (Z)-η1-allylpalladium, toward which a ring strain generated in the cyclization step leading to trans-isomers biases the equilibrium through η3-η1-η3-complex in the former cyclization. Varied diastereoselectivities were observed in the formation of five-membered carbocycles and six-membered heterocycles. These reflect release of a ring strain generated in the cyclization step leading to trans-isomers and a different distribution of the (Z)- and the (E)-η1-allylpalladium intermediates generated by the oxidative addition of allylic acetates to Pd(0) or carbopalladation of allenes, respectively. A steri-cally demanding substituent at the center of the allyl moiety is necessary for high diastereo- and enantioselectivity. The enantioselectivity of the former cyclization was lowered by the presence of organometallic reductants or reagents, possibly causing the formation of neutral η1-allylpalladium species. We used a chiral allylic acetate containing (E)-deuterium-labeled alkene to demonstrate that the electrophilic attack of the aldehyde to the allyl ligand occurred on the side where the palladium existed, consistent with the Zimmerman-Traxler transition state.
Synthesis of α-amino ketones from terminal alkynes via rhodium-catalyzed denitrogenative hydration of N -sulfonyl-1,2,3-triazoles
Miura, Tomoya,Biyajima, Tsuneaki,Fujii, Tetsuji,Murakami, Masahiro
supporting information; experimental part, p. 194 - 196 (2012/03/07)
N-Sulfonyl-1,2,3-triazoles react with water in the presence of a rhodium catalyst to produce α-amino ketones in high yield. An intermediary α-imino rhodium(II) carbenoid undergoes insertion into the O-H bond of water. This transformation formally achieves 1,2-aminohydroxylation of terminal alkynes in a regioselective fashion when combined with the copper(I)-catalyzed 1,3-dipolar cycloaddition with N-sulfonyl azides.
