2 research outputs found
How to get the optimal defibrillation lead parameters using myocardial perfusion scintigraphy in patienta with coronary artery disease
Stereoselective PCO/POC-Rearrangement of PâC-Cage Phosphorane in the Reaction of 4,5-Dimethyl-2-(2-oxo-1,2-diphenyl)ethoxy-1,3,2-dioxaphospholane with Hexafluoroacetone
Interaction
of 4,5-dimethyl-2-(2-oxo-1,2-diphenyl)Âethoxy-1,3,2-dioxaphospholane,
bearing a carboxyl group in the Îł-position with respect to the
phosphorus atom and obtained from <i>d</i>,<i>l</i>-butanediol, with hexafluoroacetone (CCl<sub>4</sub>, â40
°C) leads to the simultaneous formation of regio- and stereoisomeric
cage-like phosphoranes with phosphorusâcarbon and phosphorusâoxygen
bonds with a high stereoselectivity (>95%), whose structure was
determined by 1D and 2D NMR spectroscopy and XRD. When stored as a
solution in dichloromethane for one month, the PCO-isomer rearranges
into the thermodynamically more stable POC-isomer of the cage-like
phosphorane. Mild hydrolysis of the PCO/POC-isomers proceeds with
a high chemoselectivity and leads to the formation of PÂ(IV)-dioxaphospholane
derivatives. Acidic hydrolysis of the POC-isomer leads to the formation
of an oxirane derivative with an unexpectedly high stereoselectivity
(>95%). DFT calculations (using the PBE functional) allowed us
to obtain structures and energies of the initial phospholane, reaction
products (PCO/POC-isomers), and an intermediate PÂ(V)-oxaphosphirane