A former Goldman Sachs associate who was accused of masterminding one of the broadest insider-trading conspiracies in years was sentenced on Thursday to nearly five years in prison.

Eugene Plotkin, 28, a Harvard graduate who dabbled in filmmaking and ballroom dancing, was sentenced to four years and nine months by a federal district judge in Manhattan. The sentence was the minimum under a plea agreement.

Mr. Plotkin’s arrest in April 2006 was the first of a number of insider-trading cases brought by federal prosecutors and the Securities and Exchange Commission that year and 2007.

But none matched the scheme involving Mr. Plotkin, a fixed-income associate at Goldman, and a former co-worker, David Pajcin. Their plans involved a former Merrill Lynch analyst, a New Jersey postal worker who served on a grand jury, two workers at a magazine printing press and an exotic dancer.