Table 1.

Phosphorus chemical shifts and coupling constants of the intermediates in Scheme 4

	Chemical shiftsa (ppm)		Coupling constants (Hz)
Cpd. No.	Pa	Pb	$J_{{\mathrm{P}}_{\mathrm{a}}-{\mathrm{P}}_{\mathrm{b}}}$	JP–C
8	−9.93	−19.91	22.4	4.2
9	−18.99	—	—	5.9
10	−21.62	—	—	2.1
11	−9.56	−19.64	19.4	—
12	−21.28	−20.95	23.8	4.2

^aFor compound 12 from simulated fitting of an AB system. For all other compounds directly measured from spectra.