A pair of prominent Am Law 100 firms are helping Wal-Mart Stores Inc. take on Amazon.com Inc. in the e-commerce arena, as Wal-Mart announced Monday that it would acquire online retailer Jet.com Inc. for $3.3 billion in cash and shares.

Hoboken, New Jersey-based Jet.com was started in 2015 by Marc Lore, an entrepreneur who sold Diapers.com to Seattle-based Amazon four years earlier in a roughly $500 million deal. Fenwick & West served as special counsel on that transaction for Quidsi Inc., the e-commerce startup that owned Diapers.com and online toiletries purveyor Soap.com.