Manhattan prosecutors said the plot was driven by jealousy and greed.
Kogan, who's 67, was sentenced Friday to 12 to 36 years in prison.
The Kogans were in the throes of a harsh divorce. He was involved with a woman 20 years his junior, a publicist the couple had hired to promote an antiques business.
The widow collected about $4.3 million in life insurance after his death.
