A Unique Frustrated Lewis Pair Pathway to Remarkably Stable Borata–Alkene Systems

Abstract

The hydroboration of a conjugated diphenylphosphanylenyne with Piers' borane [HB(C 6 F 5 ) 2 ] gives three products. The major product is probably formed by generation of a geminal P/B frustrated Lewis pair that undergoes rapid and subsequent intramolecular conjugate addition of the phos-[a]

Frustrated Lewis Pair Chemistry: Development and Perspectives

“…This arrangement, together with the rather short CÀB bond infers some a-boryl carbanion character. [131,133,134] Complex 247 also shows dichotomic behavior. Toward small donor ligands (e.g.…”

“…For example, the reaction of an in situ generated geminal P/B FLP gives the zwitterionic phosphonium borata-alkene product 196 (Scheme 68). [134] The related uncatalyzed selective 1,4-hydrophosphination of dienylboranes to give 197 represents an analogous intermolecular example of this reaction (Scheme 68). [133] 6.4.…”

Design and reactions of a carbon Lewis base/boron Lewis acid frustrated Lewis pair

“…It must be noted that carbon Lewis bases have seldom been used in FLP chemistry, with notable exceptions being the N-heterocyclic carbene/B(C 6 F 5 ) 3 and related systems described by Stephan, Tamm, and others [16][17][18][19][20][21][22][23][24][25][26][27] and Alcarazo's carbodiphosphorane/B(C 6 F 5 ) 3 analogues [28][29][30][31][32]. α-Boryl carbanions might formally be candidates for new C/B FLP developments [33,34], but usually their conjugative interaction is so pronounced that they serve as borata alkenes (with their characteristic chemistry) [35][36][37] rather than as FLP systems. We thought that enamines might be interesting candidates for C/B FLP design and development, especially if such systems became available by a simple hydroboration route.…”

α-CH acidity of alkyl–B(C6F5)2 compounds – the role of stabilized borata-alkene formation in frustrated Lewis pair chemistry

“…In addition, we have recently reported the formation of zwitterionic borata-alkenes ( 3 in Scheme 2 ) by a base-free pathway. 4 …”