Kharel Sugam, Jia Tiezheng, Bhuvanesh Nattamai, Reibenspies Joseph H, Blümel Janet, Gladysz John A
Department of Chemistry, Texas A&M University, P.O. Box 30012, College Station, TX, 77842-3012, USA.
Chem Asian J. 2018 Jun 5. doi: 10.1002/asia.201800739.
Reactions of (O=)PH(OCH CH ) and BrMg(CH ) CH=CH (4.9-3.2 equiv; m=4 (a), 5 (b), 6 (c)) give the dialkylphosphine oxides (O=)PH[(CH ) CH=CH ] (2 a-c; 77-81 % after workup), which are treated with NaH and then α,ω-dibromides Br(CH ) Br (0.49-0.32 equiv; n=8 (a'), 10 (b'), 12 (c'), 14 (d')) to yield the bis(trialkylphosphine oxides) [H C=CH(CH ) ] P(=O)(CH ) (O=)P[(CH ) CH=CH ] (3 ab', 3 bc', 3 cd', 3 ca'; 79-84 %). Reactions of 3 bc' and 3 ca' with Grubbs' first-generation catalyst and then H /PtO afford the dibridgehead diphosphine dioxides (4 bc', 4 ca'; 14-19 %, n'=2m+2); P NMR spectra show two stereoisomeric species (ca. 70:30). Crystal structures of two isomers of the latter are obtained, out,out-4 ca' and a conformer of in,out-4 ca' that features crossed chains, such that the (O=)P vectors appear out,out. Whereas 4 bc' resists crystallization, a byproduct derived from an alternative metathesis mode, (CH ) P(=O)(CH ) (O=)P(CH ) , as well as 3 ab' and 3 bc', are structurally characterized. The efficiencies of other routes to dibridgehead diphosphorus compounds are compared.
（O=）PH（OCH₂CH₃）与BrMg（CH₂）ₘCH=CH（4.9 - 3.2当量；m = 4（a），5（b），6（c））反应生成二烷基氧化膦（O=）PH[（CH₂）ₘCH=CH₂]（2 a - c；后处理后产率77 - 81%），将其用NaH处理，然后与α,ω - 二溴化物Br（CH₂）ₙBr（0.49 - 0.32当量；n = 8（a'），10（b'），12（c'），14（d'））反应，得到双（三烷基氧化膦）[H₂C=CH（CH₂）ₘ]₂P（=O）（CH₂）ₙ（O=）P[（CH₂）ₘCH=CH₂]（3 ab'，3 bc'，3 cd'，3 ca'；79 - 84%）。3 bc'和3 ca'与第一代Grubbs催化剂反应，然后用H₂/PtO₂处理，得到双桥头二膦二氧化物（4 bc'，4 ca'；14 - 19%，n' = 2m + 2）；³¹P NMR光谱显示有两种立体异构体（约70:30）。获得了后者两种异构体的晶体结构，即外，外 - 4 ca'和具有交叉链的内，外 - 4 ca'的一种构象异构体，使得（O=）P向量呈外，外排列。虽然4 bc'难以结晶，但对源自另一种复分解模式的副产物（CH₂）₃P（=O）（CH₂）₃（O=）P（CH₂）₃，以及3 ab'和3 bc'进行了结构表征。比较了合成双桥头二磷化合物的其他路线的效率。
