Phosphorinanes Dioxaphosphorinanes

N.m.r. spectroscopy has played an important part in determining the stereochemistry of the 1,3-dioxaphosphorinanes (52). The presence of the saturated six-membered ring means that there are usually conformational effects to be unravelled before configurational assignments can be made. The chair conformation is generally dominant. Phosphorus substituents which exhibit shielding effects show that in many P " phosphorinanes this substituent occupies an axial position and Sis( has been used to establish the equatorial conformation of a t-butyl substituent at C(5). Even in P" derivatives the isomer possessing the bulkiest P-substituent in an axial... 

The geminal coupling of some azo1ooxaphospho1enes is reported to correlate with A.. 9 1 Vicinal couplings have been used in the conformational analysis of a variety of compounds such as dioxaphosphorinanes,92 phosphorinanes (in combination uith CNDO/2 calculations),93 and bromophosphorinanes (in combination uith dipole moment measurements).99 The various couplings for 1,1-viny1idene-diphosphonic acid and its salts have also been measured.95... 

Unlike 1,3,5-dioxaphosphorinanes the relative population of the con-former with the axial phenyl group at phosphorus decreases in 1,3,5-diazaphosphorinanes both for P(III) and for P(IV) compounds. Conformational analysis of 5-phenyl-1,3,5-diazaphosphorinanes and their oxides, sulfides, and selenides showed that the conformational equilibrium shifted toward the conformer with the axial phenyl group on changing from P(III) to P(1V) derivatives. The same conclusion made for 5-phenyl-l, 3,5-dioxaphosphorinanes, but it is contrary to that made for 1-phenyl-phosphorinane-4-ones and their derivatives (83MI1). 

An 0-18 isotopic shift on P-31 chemical shifts of epimeric 1, 3,2-dioxaphosphorinane esters (10) has been used to investigate the stereochemistry of hydroxide catalyzed hydrolysis in these aryl phosphorinane triesters. As shown in Scheme I the axial epimer of 2-(2,4-dinitrophenoxy)-2-oxo-trans-5,6-tetramethylene-l,3,2-dioxa-phosphorinane) 5a, was hydrolyzed in 0-18 enriched hydroxide. The cyclic diester, 8, was methylated with diazomethane in methanol. The P-31 NMR spectrum of the 0-18 labeled axial methyl phosporl-nane product, 2, showed three signals representing the unlabeled... 

Diethylamino-methyl)-l,3,2-dioxaphosphorinan-2-snlfid771 Zu 1,5 g (11 mmol) 2-Hydro-1,3,2(A°)-dioxa-phosphorinan-2-sulfid gibt man bei 0-2° 1,32 g (8,3 mmol) Bis-[diethylamino]-methan und erwarmt das Ge-misch 1 Stde. auf 60°. Dann wird das Diethylamin i. Vak. entfernt, der Ruckstand wird destilliert Ausbeute 1,45 g (78%) Sdp. 70-7370,008 Torr (1 Pa). 

The presumed stereochemistry of displacement of chlorine at a phosphoryl centre by a primary amine (benzylamine) and crystallographic determination of the configuration of 2-benzylamino-4-phenyl-l,3,2-dioxaphosphorinane 2-oxide has allowed an assignment of stereochemistry (trans chlorine and phenyl) in a diastereoisomeric 2-chloro-4-phenyl-l,3,2-dioxa-phosphorinane 2-oxide the more stable of the two cyclic phosphoryl chlorides has chlorine in the axial position. 

Phosphorus(y) Compounds. The chemistry of phosphate species containing a peroxy linkage and the stereochemical implications of reaction mechanisms at phosphorus(v) have been reviewed. The cyclic 1,3,2-dioxaphospholans derived from meso- and ( )-hydrobenzoin show different n.m.r. spectra, and the crystal structures of the 2-phenoxy- and 2-/>-bromophenoxy-5-chloromethyl-5-methyI-2-oxo-l,3,2-dioxaphosphorinans have been determined. Factors influencing the stereochemistry in substituted 1,3,2-dioxa-phosphorinans as shown mainly by n.m.r. data are considered in a number of papers. Changes in the O—H stretching frequency of phenol in the... 

Typical procedure. ( ) cis-2-(lsocyanomethyl) -5,5-dimethyl-2-oxo-4-phenyl-1,3,2-dioxa-phosphorinane 1618 [1207] A solution of POClj (2.4 mL, 26.0 mmol) in di-chloromethane (10 mL) was added dropwise to a stirred solution of (+)-ds-2-(formamidomethyl)-5,5-dimethyl-2-oxo-4-phenyl-l,3,2-dioxaphosphorinane (6.38 g, 22.5 mmol) and iPr2NH (9.5 mL, 67.5 mmol) in dichloromethane (130 mL) at —20 °C and the reaction mixture was stirred for 2.5 h at 0 °C. Aqueous NaHCOa (20 g in 150 mL of water) was added carefully (evolution of CO2) and the mixture was stirred for 20 min. The layers were separated and the aqueous layer was extracted with dichloromethane (3 x 30 mL). The combined organic layers were dried... 

---