You can try strcapture with regular expression:

dat = data.frame(A = c("M24656811 M24677722 GREEN,SMITH34/M/B",
                       "M24654999 DOE,JANE V37/F/W", "M24333107 DOE,JOHN24/M/B"))

# Using strcapture
pattern <- "^(\\w*) ?(M2\\d+) (\\w+,[^0-9 ]+) ?(.+)$"
result = strcapture(pattern, dat$A, 
                    proto = data.frame(A = character(),
                                       B = character(),
                                       C = character(),
                                       D = character()))
result

You can also use str_match:

result = str_match(dat$A, pattern)
result = as.data.frame(result[, -1])
colnames(result) <- c("A", "B", "C", "D")
result