Ab initio calculation of boat benzenes in bis(2,4,6-tri-t-butylphenyl) phosphinic chloride

ab initio Calculation of the benzene skeletons of the titled compound indicated that the molecule suffers 61.4 kcal/mol higher energy than that of flat benzene rings and that the boat benzene form is even more stable than the envelope or chair form benzene.     

Phosphaquinomethane and phosphathienoquinomethanes, and their anion radicals

Phosphaquinomethane and phosphathienoquinomethanes sterically protected by Mes* (Mes* = 2,4,6-tri-tert-butylphenyl) were synthesized by 1,6-dehydration of the corresponding 4-phosphinoaryl carbinols. Structural similarities to the conventional quinoid compounds were revealed by 1H, 13C, and 31P NMR study and further confirmed by X-ray crystallography of the phosphathienoquinomethane. The corresponding anion radicals were generated by reduction with sodium, and considerable delocalization of an unpaired electron was demonstrated by EPR.     

Synthesis of hexahydropyridazine-3-phosphonic acid

The synthesis of hexahydropyridazine-3-phosphonic acid (piperidazine-3-phosphonic acid) was performed via a hetero-Diels-Alder reaction followed by Lewis acid-catalyzed phosphonylation. This two-step procedure was improved to a one-pot reaction.     

(eta 5-Cyclopentadienyl)(eta 4-di- and tetra-phosphorylcyclobutadiene)cobalt(I): synthesis,structure, and formation of 1-D coordination polymer

(eta 5-Cyclopentadienyl)(eta 4-di- and tetra-phosphorylcyclobutadiene)cobalt(I) complexes were synthesized by the reaction of mono- and diphosphorylacetylenes with CpCo(CO)2, respectively. The tetraphosphoryl derivative has proved to work as a bis-bidentate ligand affording a one-dimensional coordination polymer with Ce(III).     

Synthesis of chalcones bearing 2-hydroperoxy-3-methyl-3-butenyl or 2-hydroxy-3-methyl-3-butenyl group from prenylated chalcones

Abstract

Chalcones bearing 2-hydroperoxy-3-methyl-3-butenyl or 2-hydroxy-3-methyl-3-butenyl groups, such as xanthoangelol E (1a), xanthoangelol D (2a), psorachalcone A (2?b), xanthohumol D (2c), and related derivatives were first synthesized by using the ene reaction of prenylated chalcones with singlet oxygen.     

First synthesis of lycoperdic acid

Lycoperdic acid, (2S,2′S)-2-amino-3-(2′-carboxy-5′-oxo-2′-tetrahydrofuranyl) propanoic acid, was synthesized from trans-4-hydroxy-L-proline.     

Some New Protective Groups for Stabilizing Low Coordinated Phosphorus Compounds

Abstract

Sterically stabilized diphosphenes and 1,3-diphosphaallenes by 2, 4 - tri- t - butylphenyl or 2,4,6-tri-t- pentylphenyl groups were prepared.     

X-ray structure of 3-diphenylmethylene-2-(2,4,6-tri-t-butylphenyl)thiaphosphirane 2-sulfide: The first thiaphosphirane with exo-methylene

The title compound was prepared by sulfurization of a 1-phosphaallene and its x-ray structure analysis showed the following notable features of the thiaphosphirane ring: P-S = 2.101(2), P-C = 1.770(5) and S-C = 1.767(5) Å (remarkably short), and ∠SPC = 53.5(2), ∠PSC = 53.6(2) and ∠PCS = 72.9(2)°.     

Preparation and properties of some stable captodative diphosphenes carrying the N-(9-fluorenyl)-N-mesitylamino group as an electron-donating new sterically protecting auxiliary

The N-(9-fluorenyl)-N-mesitylamino group was utilized as an electron-donating new sterically protecting group and thus several captodative 1-amino-2-aryldiphosphenes were prepared. The push-pull substituent effect on the -PP- bond was demonstrated by ³¹P NMR, and the reactivities of the captodative diphosphenes were studied.