Answer:
No. Heroin (diacetylmorphine) is a derivative of morphine that comes from the opium poppy. Buprenorphine is also a semi-synthetic opiate, but it is derived from thebaine and is considered only a partial-agonist. It is not in heroin; they are two completely different chemicals.
However, buperenorphine is used as a prescription (brand names: Suboxone, Subutex) to help heroin or other opiate-dependent persons come off of opiates. Since it is only a partial-agonist, it relieves opiate withdrawal symptoms without creating the desirable effect of a "high" as a full agonist (like heroin) would. It binds very strongly to opiate receptors in the brain, so prescription Suboxone users often have a harder time achieving a high if they use another opiate like heroin or OxyContin while Suboxone is in their system. For this reason, buprenorphine is a favorable drug to use to gradually wean users off of opiates and nurse the receptors in their brain back to health.