A 44-year-old Wellesley man has been sentenced to 18 months in jail after pleading guilty to stealing $1 million from his Cambridge-based employer. Andy Kim, who worked for an unnamed technology company, also was sentenced to a year of probation, according to U.S. Attorney’s Office in Massachusetts. Technically, Kim was charged with wire fraud, as his scheme involved the disguising of transactions that wound up placing the money in his bank account or invested funds for him.