The Phospha–Michael addition product {(t-BuNH)P(μ-N-t-Bu)2P(=N-t-Bu)—C(=CH2)CH(p-CH3O—C6H4)-P(O)[(OCH2C(CH3)2CH2O)]}

The title compound, 2-{2-[1,3-di-tert-butyl-4-(tert-butyl­amino)-2-(tert-butyl­imino)-1,3,2λ5,4-diaza­diphosphetidin-2-yl]-1-(4-meth­oxy­phen­yl)prop-2-en-1-yl}-5,5-dimethyl-1,3,2λ5-dioxaphosphinan-2-one, C31H57N4O4P3, was synthesized from the Phospha–Michael addition reaction of cyclo­diphos­pha­zane [(t-BuNH)P(μ-Nt-Bu)]2 and allenyl­phospho­nate [(OCH2C(CH3)2CH2O)P(O)C(p-CH3O—C6H4)=C=CH2]. In the crystal, N—H⋯O and C—H⋯O hydrogen bonds link the mol­ecules. The structure exhibits pseudosymmetry but attempts to solve it in a higher (monoclinic) space group were unsuccessful

Allenylphosphine oxides as simple scaffolds for phosphinoylindoles and phosphinoylisocoumarins

A range of phosphinoylindoles was prepared in one-pot from functionalized propargyl alcohols and a suitable P(III) precursor via a base-mediated reaction. The reaction proceeds via the intermediacy of allenylphosphine oxides. Similarly, phosphinoylisocoumarins were prepared from allenylphosphine oxides in a trifluoroacetic acid-mediated reaction; the latter also acts as a solvent. Interestingly, in the presence of wet trifluoroacetic acid, in addition to phosphinoylisocoumarins, phosphorus-free isocoumarins were also obtained. Key products were characterized by single crystal X-ray crystallography

Brønsted Acid Mediated Alkenylation and Copper-Catalyzed Aerobic Oxidative Ring Expansion/Intramolecular Electrophilic Substitution of Indoles with Propargyl Alcohols: A Novel One-Pot Approach to Cyclopenta[<i>c</i>]quinolines

Copper-catalyzed oxidative ring-expansion/intramolecular electrophilic substitution of 3-dienylindoles leading to cyclo­penta­[<i>c</i>]­quinolines and 3-indenyl­indoles under aerobic conditions is described. The precursors, 3-dienylindoles, are formed via Friedel–Crafts alkenylation followed by isomerization reactions of 2-substituted indoles with tertiary propargyl alcohols under Brønsted acid mediation. The methyl (sp³-C) group present in the propargyl alcohol becomes a part of a six-membered ring in the final ring-expansion products, the cyclo­penta­[<i>c</i>]­quinolines which are fluorescence active. Based on these observations, a novel one-pot strategy for ring expansion from indole to cyclo­penta­[<i>c</i>]­quinoline is discovered

Exploring organic reactions using simple cyclodiphosphazanes

Phosphine-activated reactions of alkynes/alkenes/allenes as well as the Mitsunobu reaction involve a rich phosphorus chemistry. With the aid of simple cyclodiphosphazanes, characterization of many compounds analogous to the proposed intermediates in such reactions has been accomplished. Use of a cyclodiphosphazane in Pd-catalyzed N-arylation reactions is highlighted. Results on molecular non-stoichiometry in phosphorus compounds and on the use of chiral phosphorus systems are discussed. Synthesis of allenylphosphoramides involving a cyclodiphosphazane is also described. X-ray structures of the new compounds [(t-BuNH)(PhCH2CH(CN)CH2-)P(&#956;-N-t-Bu)2P(NH-t-Bu)]+[HCO3]- (13), [(t-BuNH)P(&#956;-N-t-Bu)2P(=N-t-Bu)-C(=CH2)CH(C6H4-4-Me)-P(O)(OCH2CMe2CH2O)] (18), [(i-PrNH)P(&#956;-N-t-Bu)2P(=N-i-Pr)-N(CO2-i-Pr)-NH(CO2-i-Pr)] (24), [(S)-(2-OH-1-C10H6-1'-C10H6-2'-O-P(O)(NH-t-Bu)2] (36) and [(t-BuNH)(O)P(&#956;-N-t-Bu)2P(O)(CH=C=CMe2)] (40) are also reported

Structure and tectonics of the southwestern continental margin of India

A NNW-SSE-trending graben in the inner shelf (40-60 m isobaths), a mid-shelf basement ridge (60-150 m isobaths), a shelf-margin basin (150-1000 m isobaths) and the Prathap Ridge Complex in the slope (1000-2000 m isobaths) extend as linear features along the southwestern continental margin of India between 12°20'N and 15°00'N. The basic structural framework of the margin seems to be influenced by the pre-existing Precambrian structural fabric of the continent. The mid-shelf basement ridge and the Prathap Ridge Complex are interpreted as manifestation of the rift-phase volcanism when India separated from Madagascar around 84 Ma