Unfortunately not, except for certain reinvestments in qualified small business stock or empowerment zone business stock (see the Schedule D instructions for these special rollover rules). Apart from these exceptions, all of the gain on the sale of one stock must be reported even if other stock is purchased. The like-kind exchange rules do not apply to securities (stocks, bonds, notes, etc.).
IRA-type plan set up by an employer, rather than the employee. Salary-reduction contributions may be allowed to plans of small employers set up before 1997.