Novel compounds are provided which are glycogen phosphorylase inhibitors which are useful in treating, preventing or slowing the progression of diseases requiring glycogen phosphorylase inhibitor therapy such as diabetes and related conditions (such as hyperglycemia, impaired glucose tolerance, insulin resistance and hyperinsulinemia), the microvascular complications associated with diabetes (such as retinopathy, neuropathy, nephropathy and delayed wound healing), the macrovascular complications associated with diabetes (cardiovascular diseases such as atherosclerosis, abnormal heart function, myocardial ischemia and stroke), as well as Metabolic Syndrome and its component conditions including hypertension, obesity and dislipidemia (including hypertriglyceridemia, hypercholesterolemia and low HDL), and other maladies such as non-cardiac ischemia, infection and cancer. These novel compounds have the structure ##STR00001## or stereoisomers or prodrugs or pharmaceutically acceptable salts thereof, wherein W, R.sup.1, R.sup.2, Y and Z are defined herein.