. . "above; (e) reacting the product of step (d) with a compound of the formula P-X, wherein P is a sulfonyl activating group and X is Cl, Br or I, in the presence of a tertiary amine base to form a compound of the formula (IX) ##STR16## wherein P is a sulfonyl activating group, and R4, n, ##STR17## R and R1 are as defined above; and (f) (i) treating the product of step (e) with PCl5 in the presence of" . .