A Novel Approach to 1,2,4-Thiadiphospholes and Functionalized 1,2-Thiaphospholes

Synthesis and Reactivity of ortho-Carbaborane-Containing Chiral Aminohalophosphines

“…The P−Br bonds are slightly shorter (ca. 227 pm) than the P−Br bonds in dibromotetraphosphatetracyclononane derivatives (228.6(2) and 231.2(2) pm or 228.7(1) and 231.3(1) pm). On the other hand, they are in good accordance with the P−Br bond lengths found for 1,8-bis(dibromophosphanyl)naphthalene (between 222.53(9) and 227.37(9) pm) …”

New pathways in the reaction between the 1,2,4-triphosphole P3C2But2CH(SiMe3)2 and selenium: Crystal and molecular structures of three new cage compounds, P3Se4C2But2CH(SiMe3)2, P3Se3C2But2 H2CH(SiMe3)2 and P5Se2C4But4(CHSiMe3But)

“…Regitz and coworkers have described [4 + 2] cycloaddition reactions of both the 1,2,4-thiadiphosphole, P 2 C 2 Bu t 2 S [9], and the corresponding 1,2,4-oxadiphosphole P 2 C 2 Bu t 2 O [10] with alkynes R 0 CCR 0 . In each case the initial reaction is followed by a further retro Diels-Alder reaction involving the loss of the phospha-alkyne to afford the 1,2-thiaphosphole and 1,2-oxaphosphole, respectively (see Scheme 1).…”

“…In each case the initial reaction is followed by a further retro Diels-Alder reaction involving the loss of the phospha-alkyne to afford the 1,2-thiaphosphole and 1,2-oxaphosphole, respectively (see Scheme 1). In the case of the 1,2,4-thiadiphosphole a [4 + 2] cycloaddition reaction with the phospha-alkyne, PCBu t , gives a product which can undergo further a [2 + 2 + 2] cycloaddition with alkynes R'CCR' to give the novel cage compound shown in Scheme 1 [9].…”

“…Likewise, as shown in Scheme 2, phospha-alkynes act as dienophiles in [4 + 2] cycloaddition reactions with the 1,2,4-oxadiphosphole [10] 1,2,4-thiadiphosphole [9,11] and the 1,2,4-selenadiphosphole [12,13]. In these systems the initially formed [4 + 2] cyclo-adduct rapidly undergoes a homo Diels-Alder reaction with a second phosphaalkyne to afford the tetra-phospha cage compounds.…”

“…In the case of the 1,2,4-thiadiphosphole [9,11], the homo Diels-Alder reaction of the intermediate bicyclodiene with the phospha-alkyne occurs regiospecifically, but reactions involving either the 1,2,4-selenadiphosphole [12,13] or the 1,2,4-oxadiphosphole [10] afford both regioisomers, which have been fully structurally characterised. The intermediates in these reactions could not be detected even by 31 P NMR spectroscopy.…”