Rigid, Fluoroarene-Containing Phosphonium Borates and Boranes: Syntheses and Reactivity Studies
摘要:
The reaction of (C6F5)(2)B(OEt) with (Bu2P)-Bu-t(CH2Li) yields the cyclic phosphonium ethoxyborate (C6F5)(OEt)B(CH2)(C6F4)(PBu2)-Bu-t ([1]OEt) via B-C adduct formation and ortho-fluoride substitution. Treatment of [1]OEt with HCl in Et2O gives the chloroborate [1]Cl in almost quantitative yield. The reaction of [1]Cl with Li[AlH4] leads not only to the reduction of the B-Cl bond but also to the selective substitution of one fluorine atom on the tetrafluorophenylene bridge ([4]H). [1]Cl is readily transformed into [1]F, [1]OAc, and [1]OTf upon reaction with Tl[PF6], AgOAc, and AgOTf, respectively (OAc = acetate; OTf = triflate). [1]OTf represents a convenient storage form of [1](+), because its B-O bond is highly labile. The free Lewis acid [1](+) was prepared in the form of its aluminate salt [1](+)[Al((OBuF)-Bu-t)4](-). The phenyl derivative of [1]OEt, (C6H5)(OEt)B(CH2)(C6F4)1)(PBu2)-Bu-t ([5]OEt), is also accessible and serves as starting material for the preparation of [5]Cl and [5](+)[Al((OBuF)-Bu-t)(4)](-).
CC Coupling by Thermolysis of Alkynyl Phosphonium Borates
作者:Xiaoxi Zhao、Thomas M. Gilbert、Douglas W. Stephan
DOI:10.1002/chem.201001575
日期:2010.9.10
When the heat is on, alkynylphosphoniumborates, tBu2PHCCBH(C6F5)2 and (tBu2PCCB(C6F5)2)(BuCH2CH)(tBu2PCCB(C6F5)2), undergo CCcoupling reactions leading to a C4 alkene derivative, (tBu2PCHBF(C6F4)(C6F5)CH)2, and a cumulene derivative, (tBu2P)C6F4BF(C6F5)C4B(C6F5)2(BuCH2CH)(PtBu2), respectively (see figure).
当热是上,炔基鏻硼酸盐,吨卜2 PHCCBH(C 6 ˚F 5)2和(吨卜2 PCCB(C 6 ˚F 5)2)(布赫2 CH)(吨卜2 PC CB(C 6 F 5)2),经历CC偶联反应,生成C 4烯烃衍生物,(t Bu 2 PCHBF(C 6 F 4)(C 6 F 5)CH)2和异丙苯衍生物(t Bu 2 P)C 6 F 4 BF(C 6 F 5)C 4 B(C 6 F 5)2(BuCH 2 CH)(P t Bu 2)分别(见图)。