“The move is likely to immediately expand the box-office potential of a show that has been extensively revised since receiving mixed reviews in its initial performances in Atlanta last year. Now titled “Oprah Winfrey Presents: ‘The Color Purple,’ ” the musical will begin previews at the Broadway Theater on Nov. 1 and open on Dec. 1. In what is her first Broadway venture, Ms. Winfrey will contribute more than $1 million of the musical’s $10 million production cost.”