Diphosphanes derived from phobane and phosphatrioxa-adamantane: similarities, differences and anomalies
作者:Deborah L. Dodds、Joelle Floure、Michael Garland、Mairi F. Haddow、Thomas R. Leonard、Claire L. McMullin、A. Guy Orpen、Paul G. Pringle
DOI:10.1039/c1dt10335k
日期:——
The homodiphosphanes CgP–PCg (1) and PhobP–PPhob (2) and the heterodiphosphanes CgP–PPhob (3), CgP–PPh2 (4a), CgP–P(o-Tol)2 (4b), CgP–PCy2 (4c), CgP–PtBu2 (4d), PhobP–PPh2 (5a), PhobP–P(o-Tol)2 (5b), PhobP–PCy2 (5c), PhobP–PtBu2 (5d) where CgP = 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamant-9-yl and PhobP = 9-phosphabicyclo[3.3.1]nonan-9-yl have been prepared from CgP(BH3)Li or PhobP(BH3)Li and the appropriate halophosphine. The formation of 1 is remarkably diastereoselective, with the major isomer (97% of the product) assigned to rac-1. Restricted rotation about the P–P bond of the bulky meso-1 is detected by variable temperature 31P NMR spectroscopy. Diphosphane 3 reacts with BH3 to give a mixture of CgP(BH3)–PPhob and CgP–PPhob(BH3) which was unexpected in view of the predicted much greater electron-richness of the PhobP site. Each of the diphosphanes was treated with dimethylacetylene dicarboxylate (DMAD) in order to determine their propensity for diphosphination. The homodiphosphanes 1 and 2 did not react with DMAD. The CgP-containing heterodiphosphanes 4a–d all added to DMAD to generate the corresponding cisalkenes CgPCH(CO2Me)CH(CO2Me)PR2 (6a–d) which have been used in situ to form chelate complexes of the type [MCl2(diphos)] (7a–d) where M = Pd or Pt. The PhobP-containing heterodiphosphanes 3 and 5a–d react anomalously with DMAD and do not give the products of diphosphination. The X-ray crystal structures of the diphosphanes 2, 3, 4a, and 5a, the monoxide and dioxide of diphosphane 1, and the platinum chelate complex 7c have been determined and their structures are discussed.
同种二膦CgP–PCg(1)和PhobP–PPhob(2)以及异种二膦CgP–PPhob(3)、CgP–PPh2(4a)、CgP–P(o-Tol)2(4b)、CgP–PCy2(4c)、CgP–PtBu2(4d)、PhobP–PPh2(5a)、PhobP–P(o-Tol)2(5b)、PhobP–PCy2(5c)、PhobP–PtBu2(5d)(其中CgP=6-膦-2,4,8-三氧-1,3,5,7-四甲基金刚烷-9-基,PhobP=9-磷双环[3.3.1]壬-9-基)已由CgP(BH3)Li或PhobP(BH3)Li与相应的膦卤化物制备得到。1的形成具有显著的非对映选择性,主要异构体(产物97%)被指定为外消旋-1。通过变温31P核磁共振波谱检测到庞大的内消旋-1中的P—P键的旋转受阻。二膦3与BH3反应得到CgP(BH3)–PPhob和CgP–PPhob(BH3)的混合物,这与预测的PhobP位点具有更强的给电子性不相符。每种二膦都与二甲基乙炔二羧酸酯(DMAD)反应,以确定其双膦化的倾向。同种二膦1和2不与DMAD反应。含CgP的异种二膦4a~d都与DMAD加成并生成了相应顺式烯烃CgPCH(CO2Me)CH(CO2Me)PR2(6a~d),它们已被用于原位形成螯合型配合物[MCl2(diphos)](7a~d)(M=Pd或Pt)。含PhobP的异种二膦3和5a~d与DMAD反常地反应且不生成双膦化产物。已测定二膦2、3、4a、5a、1的一氧化物和二氧化物以及铂螯合物7c的X射线晶体结构,并讨论了它们的结构。