I am able to set initial extent with wkid 102100
var map = new Map({ basemap: "topo" });
var extent = new Extent({
xmin: -8499854.09025499,
ymin: 4383842.034757545,
xmax: -8429713.995449727,
ymax: 4422987.654383438,
spatialReference: 102100 });
var view = new MapView({
container: "viewDiv",
map: map,
extent: extent });
but I won't be able to set initial extent correctly with other wkid, like
var extent = new Extent({
xmin: 940000.0000547133,
ymin: 1160000.0002149716,
xmax: 1100000.0002790727,
ymax: 1370000.0002149716,
spatialReference: 102671 })
});