Syn to anti isomerization and degradation of phosphines of the 7-phosphanorbornene system by action of methanol

Synthesis of acyl(chloro)phosphines enabled by phosphinidene transfer

“…This type of formal reductive elimination from l-5 phosphoranes to give a phosphorus(III) product has previously been described in the literature. [47][48][49][50] Finally, we investigated the possibility of a phosphenium chloride salt intermediate (I2, see ESI †), which would arise from loss of anthracene from cation 3 and is the formal reverse of the McCormack reaction. [49][50][51] We found the relative Gibbs free energy of intermediate I2 to be 65.0 kcal mol À1 which is signicantly higher than either TS1 of TS2, ostensibly ruling it out as an intermediate in the reaction mechanism (see ESI †).…”

1,4,2‐Diazaphospholidine‐3,5‐diones and Related Compounds: A Lecture on Unpredictability in Catalysis

“…As it is highly unlikely that the P atom in the 6 –MeNCO attacks the second isocyanate (in this case 2‐propyl isocyanate) the mechanism of this new reaction differs considerably from that proposed for the retro‐McCormack reactions discussed in Ref. 10a, b, in which the formation of phosphorane‐type activated species involving both oxygen nucleophiles in a P‐centered intermediate is proposed (Scheme ).…”

“…There are also only two preparative examples of the extrusion of a 1,3‐diene from an unsaturated phosphacycle, such as 6 . 10a, b In both cases, oxygen‐containing nucleophiles (diethyl peroxide and methanol, respectively) induce the fragmentation.…”

Stereochemistry of the reaction of oxygen nucleophiles with a phosphinous chloride in the 7-phosphanorbornene series

“…Phosphinite (7) was quite unstable when heated in methanol; after 1 day, complete loss of the P bridge occurred. An intermediate (11) such as that proposed for the related reaction occurring between tertiary 7-PNB phosphines and methanol 1 1 * 1 2 may be involved. The identity of the ejected fragment [shown as (13)]…”