Table 2. Key Distances (Å) in Structures Optimized with QM/MM Method^a.

state	r1	r2	r3	r4	r5	r6	r7	r8	r9
C2	3.00	1.69	4.67	1.90	1.04	2.93	1.00	1.90	2.88
B	2.97	1.70	4.65	1.87	1.04	2.90	1.45	1.15	2.60
Int	1.94	1.88	3.80	1.62	1.08	2.70	1.98	1.00	3.01
P	1.69	3.04	4.70	1.01	1.71	2.71	2.98	1.03	3.89
crystal	N/A	1.60	N/A	N/A	N/A	3.06	N/A	N/A	3.65

^aReaction coordinates r1–r9 are defined in Figure 2. The two pre-cleavage states, C2 and B, the dianionic phosphorane intermediate state, Int, and the post-cleavage state, P, are depicted in Figure 3. The crystal structure used herein (ref (11)) does not contain A-1(O2′).