名称:
Cyclodiphosph(III)azane chemistry – Ylides from the reaction of [(RNH)P-N(t-Bu)]2 [R=t-Bu, i-Pr] with dimethyl maleate and chiral ansa-type derivatives from reaction of [ClP-N(t-Bu)]2 with a substituted BINOL
摘要:
Use of a simple inorganic ring system with the cyclodiphosph(III) azane skeleton [e.g. [(RNH)P-N(t-Bu)](2) [R = t-Bu (7), i-Pr (8)] to probe some of the intermediates proposed in phosphine mediated organic reactions is highlighted. Thus the reaction of 7-8 with the allenylphosphine oxide Ph2P(O)C(Ph)=C=CH2 (9) affords the phosphinimines [(RNH)P(mu-N-t-Bu)(2)P(=N-R)-C(=CH2) CH(Ph)-P(O)Ph-2] [R= t-Bu (10), i-Pr (11)], while a similar reaction of 7-8 with dimethyl maleate (or dimethyl fumarate) affords the ylides [(RNH) P(mu-N-t-Bu)(2)P(NH-R)=C(CO2Me)-CH2(CO2Me) [R = t-Bu (18), i-Pr (19)]. The implication of such reactions on phosphine mediated organic transformations including Morita-Baylis-Hillman reaction is mentioned. In a rather rare type of situation, an unusually long phosphoryl (P=O) bond [1.538 (5) angstrom] as revealed the X-ray structure of {(R)-6,6'-(t-Bu)(2)-1,1'-(C10H5)(2)-2,2'-O-2-}{P(O)(N-t-Bu)(2)-P(Se)} (27) is rationalized by means of crystallographic disorder in packing after comparing the data with that in the literature and {1,1'-(C10H6)(2)-2,2'-O-2}{P(Se)(N-t-Bu)(2)-P(Se)} (29). X-ray structures of the new compounds 10-11, 18-19, 27 and 29 are discussed. Compound 10 crystallizes in the chiral space group Pca2(1) with (S)-chirality at the carbon center [-C(=CH2) CH(Ph)-P] suggesting a case of spontaneous resolution through crystallization. (C) 2011 Elsevier B.V. All rights reserved.