A coalition of business and insurance groups is lobbying lawmakers against Massachusetts Gov. Deval Patrick’s plan to collect millions of dollars from them to help close a $130 million funding gap this year for the state’s health insurance law. The coalition is pushing an alternative that would require all Massachusetts Medicaid patients to join managed care plans. The coalition says mandatory managed care would save the state $160 million this fiscal year and between $690 million and $1 billion by 2013. The Patrick administration disputes the contention that the managed care proposal would save money.