[​4+2] versus [​2+2] Homodimerization in P(V) Derivatives of 2,4-Disubstituted Phospholes

Table 1

³¹P NMR chemical shifts (ppm) (CDCl₃) of 1, 2, and 3.

Entry	R	1	2	3
1	Ph; (a)	11.3	47.8	55.8 (d, = 37.6 Hz); 76.3 (d, = 37.6 Hz)
2	Trimethylsilyl; (b)	31.9	59.0	64.4 (d, = 37.0 Hz); 83.2 (d, = 37.0 Hz)
3	t-Butyl; (c)	1.4	47.5	No dimer