Phosphine construction materials

The same phosphine-borane used for the synthesis of BisP acted as the starting materials of the construction of MiniPHOS, the next smaller analogue to BisP (Scheme 13). The chirally induced lithium salt was treated with alkylphos-phorus dichloride, methylmagnesium bromide, and borane-THF complex to afford enantiomerically pure MiniPHOS-borane 82a. Recrystallization enabled elimination of a small amount of corresponding raeso-diastereomer formed [29]. Yields were generally low, ranging from 13 to 28%. 

The [4+3] cycloaddition reaction offers a convenient way to prepare relatively complex seven-membered rings from simple starting materials. Using MBH adducts 352 as C3 component, a phosphine-catalyzed [4 + 3] annulation has been developed to construct the bicyclo[3.2.2]nonadiene skeleton (Scheme 4.112). The reactions proceeds smoothly with various MBH adducts as well as various substituted pyrones 353 such as ester, nitrile and amide substituted pyrones, resulting in compounds 354 in moderate to good yields. 

In turn, Phobane-H may serve as starting material for the construction of a variety of tertiary phosphines (Scheme 2.5). Noteworthy, pathway (a) via the corresponding chlorophosphine and final alkylation also affords some undesired dimeric P-P coupling products. Alternatively, a chloro-free access has been suggested, which circumvents the Phobane-Cl (pathway b). A palladium-catalyzed P-C coupling reaction (with R = Ar) is less sensitive toward moisture and allows also the incorporation of a third P-substituent bearing functional... 

Pure phosphine and its mixtures are shipped in DOT/TC approved cylinders in accordance with regulations governing the shipment of Poison Gas, Hazard Zone A materials. Shipment is permitted in specification 3A1800, 3AA1800, 3AL1800, or 3E1800 cylinders. Use of existing specification 33 or 3D cylinders is also authorized, but new construction is not authorized. 

The construction of carbon-rich materials using platinum(ii) phosphine systems is probably one of the most active areas of research in the past decade. The transsquare planar geometry adopted by the platinum(ii) center provides a versatile motif for the construction of one-dimensional linear structures, while the corresponding ds-geometry could serve as connectors at an angle. 

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